[go: up one dir, main page]

MX2013008604A - Proceso para la preparacion de 4-amino-3-cloro-5-fluoro-6-picolina tos (sustituidos). - Google Patents

Proceso para la preparacion de 4-amino-3-cloro-5-fluoro-6-picolina tos (sustituidos).

Info

Publication number
MX2013008604A
MX2013008604A MX2013008604A MX2013008604A MX2013008604A MX 2013008604 A MX2013008604 A MX 2013008604A MX 2013008604 A MX2013008604 A MX 2013008604A MX 2013008604 A MX2013008604 A MX 2013008604A MX 2013008604 A MX2013008604 A MX 2013008604A
Authority
MX
Mexico
Prior art keywords
picolinates
fluoro
chloro
amino
preparation
Prior art date
Application number
MX2013008604A
Other languages
English (en)
Other versions
MX339636B (es
Inventor
Yuanming Zhu
James M Renga
Robert D Froese
Kim E Arndt
Gregory T Whiteker
Original Assignee
Dow Agrosciences Llc
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Dow Agrosciences Llc filed Critical Dow Agrosciences Llc
Publication of MX2013008604A publication Critical patent/MX2013008604A/es
Publication of MX339636B publication Critical patent/MX339636B/es

Links

Classifications

    • CCHEMISTRY; METALLURGY
    • C07ORGANIC CHEMISTRY
    • C07DHETEROCYCLIC COMPOUNDS
    • C07D213/00Heterocyclic compounds containing six-membered rings, not condensed with other rings, with one nitrogen atom as the only ring hetero atom and three or more double bonds between ring members or between ring members and non-ring members
    • C07D213/02Heterocyclic compounds containing six-membered rings, not condensed with other rings, with one nitrogen atom as the only ring hetero atom and three or more double bonds between ring members or between ring members and non-ring members having three double bonds between ring members or between ring members and non-ring members
    • C07D213/04Heterocyclic compounds containing six-membered rings, not condensed with other rings, with one nitrogen atom as the only ring hetero atom and three or more double bonds between ring members or between ring members and non-ring members having three double bonds between ring members or between ring members and non-ring members having no bond between the ring nitrogen atom and a non-ring member or having only hydrogen or carbon atoms directly attached to the ring nitrogen atom
    • C07D213/60Heterocyclic compounds containing six-membered rings, not condensed with other rings, with one nitrogen atom as the only ring hetero atom and three or more double bonds between ring members or between ring members and non-ring members having three double bonds between ring members or between ring members and non-ring members having no bond between the ring nitrogen atom and a non-ring member or having only hydrogen or carbon atoms directly attached to the ring nitrogen atom with hetero atoms or with carbon atoms having three bonds to hetero atoms with at the most one bond to halogen, e.g. ester or nitrile radicals, directly attached to ring carbon atoms
    • C07D213/78Carbon atoms having three bonds to hetero atoms, with at the most one bond to halogen, e.g. ester or nitrile radicals
    • C07D213/79Acids; Esters
    • C07D213/803Processes of preparation
    • C07D213/807Processes of preparation by oxidation of pyridines or condensed pyridines
    • CCHEMISTRY; METALLURGY
    • C07ORGANIC CHEMISTRY
    • C07DHETEROCYCLIC COMPOUNDS
    • C07D213/00Heterocyclic compounds containing six-membered rings, not condensed with other rings, with one nitrogen atom as the only ring hetero atom and three or more double bonds between ring members or between ring members and non-ring members
    • C07D213/02Heterocyclic compounds containing six-membered rings, not condensed with other rings, with one nitrogen atom as the only ring hetero atom and three or more double bonds between ring members or between ring members and non-ring members having three double bonds between ring members or between ring members and non-ring members
    • C07D213/04Heterocyclic compounds containing six-membered rings, not condensed with other rings, with one nitrogen atom as the only ring hetero atom and three or more double bonds between ring members or between ring members and non-ring members having three double bonds between ring members or between ring members and non-ring members having no bond between the ring nitrogen atom and a non-ring member or having only hydrogen or carbon atoms directly attached to the ring nitrogen atom
    • C07D213/60Heterocyclic compounds containing six-membered rings, not condensed with other rings, with one nitrogen atom as the only ring hetero atom and three or more double bonds between ring members or between ring members and non-ring members having three double bonds between ring members or between ring members and non-ring members having no bond between the ring nitrogen atom and a non-ring member or having only hydrogen or carbon atoms directly attached to the ring nitrogen atom with hetero atoms or with carbon atoms having three bonds to hetero atoms with at the most one bond to halogen, e.g. ester or nitrile radicals, directly attached to ring carbon atoms
    • C07D213/72Nitrogen atoms
    • AHUMAN NECESSITIES
    • A01AGRICULTURE; FORESTRY; ANIMAL HUSBANDRY; HUNTING; TRAPPING; FISHING
    • A01NPRESERVATION OF BODIES OF HUMANS OR ANIMALS OR PLANTS OR PARTS THEREOF; BIOCIDES, e.g. AS DISINFECTANTS, AS PESTICIDES OR AS HERBICIDES; PEST REPELLANTS OR ATTRACTANTS; PLANT GROWTH REGULATORS
    • A01N43/00Biocides, pest repellants or attractants, or plant growth regulators containing heterocyclic compounds
    • A01N43/34Biocides, pest repellants or attractants, or plant growth regulators containing heterocyclic compounds having rings with one nitrogen atom as the only ring hetero atom
    • A01N43/40Biocides, pest repellants or attractants, or plant growth regulators containing heterocyclic compounds having rings with one nitrogen atom as the only ring hetero atom six-membered rings
    • CCHEMISTRY; METALLURGY
    • C07ORGANIC CHEMISTRY
    • C07DHETEROCYCLIC COMPOUNDS
    • C07D213/00Heterocyclic compounds containing six-membered rings, not condensed with other rings, with one nitrogen atom as the only ring hetero atom and three or more double bonds between ring members or between ring members and non-ring members
    • C07D213/02Heterocyclic compounds containing six-membered rings, not condensed with other rings, with one nitrogen atom as the only ring hetero atom and three or more double bonds between ring members or between ring members and non-ring members having three double bonds between ring members or between ring members and non-ring members
    • C07D213/04Heterocyclic compounds containing six-membered rings, not condensed with other rings, with one nitrogen atom as the only ring hetero atom and three or more double bonds between ring members or between ring members and non-ring members having three double bonds between ring members or between ring members and non-ring members having no bond between the ring nitrogen atom and a non-ring member or having only hydrogen or carbon atoms directly attached to the ring nitrogen atom
    • C07D213/60Heterocyclic compounds containing six-membered rings, not condensed with other rings, with one nitrogen atom as the only ring hetero atom and three or more double bonds between ring members or between ring members and non-ring members having three double bonds between ring members or between ring members and non-ring members having no bond between the ring nitrogen atom and a non-ring member or having only hydrogen or carbon atoms directly attached to the ring nitrogen atom with hetero atoms or with carbon atoms having three bonds to hetero atoms with at the most one bond to halogen, e.g. ester or nitrile radicals, directly attached to ring carbon atoms
    • C07D213/78Carbon atoms having three bonds to hetero atoms, with at the most one bond to halogen, e.g. ester or nitrile radicals
    • C07D213/79Acids; Esters
    • CCHEMISTRY; METALLURGY
    • C07ORGANIC CHEMISTRY
    • C07DHETEROCYCLIC COMPOUNDS
    • C07D213/00Heterocyclic compounds containing six-membered rings, not condensed with other rings, with one nitrogen atom as the only ring hetero atom and three or more double bonds between ring members or between ring members and non-ring members
    • C07D213/02Heterocyclic compounds containing six-membered rings, not condensed with other rings, with one nitrogen atom as the only ring hetero atom and three or more double bonds between ring members or between ring members and non-ring members having three double bonds between ring members or between ring members and non-ring members
    • C07D213/04Heterocyclic compounds containing six-membered rings, not condensed with other rings, with one nitrogen atom as the only ring hetero atom and three or more double bonds between ring members or between ring members and non-ring members having three double bonds between ring members or between ring members and non-ring members having no bond between the ring nitrogen atom and a non-ring member or having only hydrogen or carbon atoms directly attached to the ring nitrogen atom
    • C07D213/60Heterocyclic compounds containing six-membered rings, not condensed with other rings, with one nitrogen atom as the only ring hetero atom and three or more double bonds between ring members or between ring members and non-ring members having three double bonds between ring members or between ring members and non-ring members having no bond between the ring nitrogen atom and a non-ring member or having only hydrogen or carbon atoms directly attached to the ring nitrogen atom with hetero atoms or with carbon atoms having three bonds to hetero atoms with at the most one bond to halogen, e.g. ester or nitrile radicals, directly attached to ring carbon atoms
    • C07D213/78Carbon atoms having three bonds to hetero atoms, with at the most one bond to halogen, e.g. ester or nitrile radicals
    • C07D213/79Acids; Esters
    • C07D213/803Processes of preparation
    • CCHEMISTRY; METALLURGY
    • C07ORGANIC CHEMISTRY
    • C07DHETEROCYCLIC COMPOUNDS
    • C07D213/00Heterocyclic compounds containing six-membered rings, not condensed with other rings, with one nitrogen atom as the only ring hetero atom and three or more double bonds between ring members or between ring members and non-ring members
    • C07D213/02Heterocyclic compounds containing six-membered rings, not condensed with other rings, with one nitrogen atom as the only ring hetero atom and three or more double bonds between ring members or between ring members and non-ring members having three double bonds between ring members or between ring members and non-ring members
    • C07D213/04Heterocyclic compounds containing six-membered rings, not condensed with other rings, with one nitrogen atom as the only ring hetero atom and three or more double bonds between ring members or between ring members and non-ring members having three double bonds between ring members or between ring members and non-ring members having no bond between the ring nitrogen atom and a non-ring member or having only hydrogen or carbon atoms directly attached to the ring nitrogen atom
    • C07D213/60Heterocyclic compounds containing six-membered rings, not condensed with other rings, with one nitrogen atom as the only ring hetero atom and three or more double bonds between ring members or between ring members and non-ring members having three double bonds between ring members or between ring members and non-ring members having no bond between the ring nitrogen atom and a non-ring member or having only hydrogen or carbon atoms directly attached to the ring nitrogen atom with hetero atoms or with carbon atoms having three bonds to hetero atoms with at the most one bond to halogen, e.g. ester or nitrile radicals, directly attached to ring carbon atoms
    • C07D213/78Carbon atoms having three bonds to hetero atoms, with at the most one bond to halogen, e.g. ester or nitrile radicals
    • C07D213/84Nitriles
    • CCHEMISTRY; METALLURGY
    • C07ORGANIC CHEMISTRY
    • C07DHETEROCYCLIC COMPOUNDS
    • C07D213/00Heterocyclic compounds containing six-membered rings, not condensed with other rings, with one nitrogen atom as the only ring hetero atom and three or more double bonds between ring members or between ring members and non-ring members
    • C07D213/02Heterocyclic compounds containing six-membered rings, not condensed with other rings, with one nitrogen atom as the only ring hetero atom and three or more double bonds between ring members or between ring members and non-ring members having three double bonds between ring members or between ring members and non-ring members
    • C07D213/89Heterocyclic compounds containing six-membered rings, not condensed with other rings, with one nitrogen atom as the only ring hetero atom and three or more double bonds between ring members or between ring members and non-ring members having three double bonds between ring members or between ring members and non-ring members with hetero atoms directly attached to the ring nitrogen atom

Landscapes

  • Chemical & Material Sciences (AREA)
  • Organic Chemistry (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Health & Medical Sciences (AREA)
  • Pest Control & Pesticides (AREA)
  • Plant Pathology (AREA)
  • Agronomy & Crop Science (AREA)
  • Engineering & Computer Science (AREA)
  • Dentistry (AREA)
  • General Health & Medical Sciences (AREA)
  • Wood Science & Technology (AREA)
  • Zoology (AREA)
  • Environmental Sciences (AREA)
  • Pyridine Compounds (AREA)
  • Low-Molecular Organic Synthesis Reactions Using Catalysts (AREA)

Abstract

Se preparan 4-amino-3-cloro-5-fluoro-6-picolinatos (sustituidos) de forma conveniente a partir de 3,4,5,6-tetracloropicolinonitrilo por medio de una serie de etapas que incluyen intercambio de flúor, aminación, reacción con hidrazina, halogenación, hidrólisis y esterificación y acoplamiento asistido por metal de transición.
MX2013008604A 2011-01-25 2012-01-24 Proceso para la preparacion de 4-amino-3-cloro-5-fluoro-6-picolina tos (sustituidos). MX339636B (es)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
US201161435974P 2011-01-25 2011-01-25
PCT/US2012/022288 WO2012103044A1 (en) 2011-01-25 2012-01-24 Process for the preparation of 4-amino-3-chloro-5-fluoro-6-(substituted)picolinates

Publications (2)

Publication Number Publication Date
MX2013008604A true MX2013008604A (es) 2013-08-12
MX339636B MX339636B (es) 2016-06-01

Family

ID=46544649

Family Applications (1)

Application Number Title Priority Date Filing Date
MX2013008604A MX339636B (es) 2011-01-25 2012-01-24 Proceso para la preparacion de 4-amino-3-cloro-5-fluoro-6-picolina tos (sustituidos).

Country Status (20)

Country Link
US (2) US8609853B2 (es)
EP (2) EP2901857B1 (es)
JP (1) JP5739019B2 (es)
KR (2) KR101517313B1 (es)
CN (1) CN103429082B (es)
AR (1) AR085023A1 (es)
AU (1) AU2012209280B2 (es)
BR (2) BR102012001638A8 (es)
CA (1) CA2825389C (es)
CO (1) CO6731128A2 (es)
HK (1) HK1206938A1 (es)
IL (1) IL227645B (es)
MX (1) MX339636B (es)
PL (2) PL2667713T3 (es)
RU (1) RU2539578C1 (es)
SG (2) SG192579A1 (es)
TW (2) TWI520943B (es)
UA (1) UA105610C2 (es)
WO (1) WO2012103044A1 (es)
ZA (1) ZA201305579B (es)

Families Citing this family (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
TW201609651A (zh) 2013-11-12 2016-03-16 陶氏農業科學公司 用於氟化化合物之過程(一)
TW201524956A (zh) * 2013-11-12 2015-07-01 Dow Agrosciences Llc 用於氟化化合物之過程(二)
TW201609652A (zh) 2013-11-12 2016-03-16 陶氏農業科學公司 用於氟化化合物之過程(三)
TWI726900B (zh) 2015-08-04 2021-05-11 美商陶氏農業科學公司 用於氟化化合物之過程
RU2018130270A (ru) * 2016-01-22 2020-02-25 ДАУ АГРОСАЙЕНСИЗ ЭлЭлСи Способ получения 4-алкокси-3-ацетоксипиколиновых кислот
AU2017268424B2 (en) * 2016-05-19 2021-07-15 Corteva Agriscience Llc Synthesis of 6-aryl-4-aminopicolinates and 2-aryl-6-aminopyrimidine-4-carboxylates by direct suzuki coupling
CN113015721B (zh) 2018-09-19 2025-07-25 科迪华农业科技有限责任公司 毒莠定卤素类似物的制备
CN115298167A (zh) 2020-03-18 2022-11-04 科迪华农业科技有限责任公司 6-芳基-4-氨基吡啶甲酸酯的改进合成
US20230357155A1 (en) 2020-03-18 2023-11-09 Corteva Agriscience Llc Improved synthesis of 4-amino-6-(heterocyclic)picolinates

Family Cites Families (23)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3629424A (en) * 1967-12-26 1971-12-21 Dow Chemical Co Cyanofluoropyridines and fungicidal compositions and methods for using the same
US3803159A (en) * 1967-12-26 1974-04-09 Dow Chemical Co Fluorine containing cyanopyridines
US3755338A (en) * 1970-12-17 1973-08-28 Dow Chemical Co 4-amino-6-bromo-3,5-dichloropicolinic acid compounds
US3971799A (en) * 1974-12-27 1976-07-27 The Dow Chemical Company Preparation of 3,5,6-trichloropicolinic acid
US4087431A (en) * 1976-05-17 1978-05-02 The Dow Chemical Company Preparation of 3,6-dichloropicolinic acid
US4814456A (en) * 1986-02-10 1989-03-21 The Dow Chemical Company Chlorinating waste streams to recover cyanopyridine contained therein
US4999432A (en) * 1989-08-28 1991-03-12 Dowelanco Fluorination with hydrogen fluoride
US5710106A (en) * 1996-02-22 1998-01-20 American Cyanamid Company Substituted pyridine herbicidal agents
JP3731982B2 (ja) * 1997-08-26 2006-01-05 株式会社日本触媒 有機フッ素化合物の製造方法
PT1246802E (pt) * 2000-01-14 2007-06-18 Dow Agrosciences Llc 4-aminopicolinatos e sua utilização como herbicidas.
US6297197B1 (en) 2000-01-14 2001-10-02 Dow Agrosciences Llc 4-aminopicolinates and their use as herbicides
AR037228A1 (es) * 2001-07-30 2004-11-03 Dow Agrosciences Llc Compuestos del acido 6-(aril o heteroaril)-4-aminopicolinico, composicion herbicida que los comprende y metodo para controlar vegetacion no deseada
UA82358C2 (uk) * 2003-04-02 2008-04-10 Дау Агросайенсиз Ллс 6-алкіл або алкеніл-4-амінопіколінати гербіцидна композиція, спосіб боротьби з небажаною рослинністю
UA81177C2 (uk) * 2003-08-04 2007-12-10 Дау Агросайєнсіз Ллс 6-(1,1-дифторалкіл)-4-амінопіколінати та їх використання як гербіцидів
WO2006062979A1 (en) * 2004-12-06 2006-06-15 E.I. Dupont De Nemours And Company Herbicidal 6-cyclopropyl-substitute 4-aminopicolinic acid derivatives
RU2428416C2 (ru) * 2006-01-13 2011-09-10 Дау Агросайенсиз Ллс 6-(полизамещенный арил)-4-аминопиколинаты и их применение в качестве гербицидов
WO2008020799A1 (en) 2006-08-18 2008-02-21 Astrazeneca Ab Thienopyrimidin-4-one and thienopyridazin-7-one derivatives as mch rl antagonists
PL2193120T3 (pl) * 2007-10-02 2017-01-31 Dow Agrosciences Llc Kwasy 2'podstowione-6-amino-5-alkilo-, alkenylo- lub alkinylo-4-pirymidynokarboksylowe i kwasy 6-podstawione-4-amino-3-alkilo-, alkenylo- lub alkinylopikolinowe oraz ich zastosowanie jako herbicydy
CA2740340A1 (en) * 2008-11-17 2010-05-20 Ishihara Sangyo Kaisha, Ltd. Pyridine derivative or its salt, pesticide containing it and process for its production
US8252938B2 (en) * 2009-06-08 2012-08-28 Dow Agrosciences, Llc. Process for the preparation of 6-(aryl)-4-aminopicolinates
GB0910766D0 (en) * 2009-06-22 2009-08-05 Syngenta Ltd Chemical compounds
DE102009054573A1 (de) 2009-11-13 2011-05-19 Tracoe Medical Gmbh Tracheostomiekanüle mit Fenster
UA103272C2 (uk) * 2009-12-11 2013-09-25 Ф. Хоффманн-Ля Рош Аг 2-аміно-5,5-дифтор-5,6-дигідро-4h-оксазини як інгібітори bace1 і/або bace2

Also Published As

Publication number Publication date
SG10201503717PA (en) 2015-06-29
TWI520943B (zh) 2016-02-11
CN103429082A (zh) 2013-12-04
TW201307290A (zh) 2013-02-16
IL227645A0 (en) 2013-09-30
RU2539578C1 (ru) 2015-01-20
TW201600511A (zh) 2016-01-01
AU2012209280B2 (en) 2015-08-20
PL2667713T3 (pl) 2017-08-31
KR20150006073A (ko) 2015-01-15
EP2901857B1 (en) 2017-03-01
TWI547482B (zh) 2016-09-01
IL227645B (en) 2018-01-31
AU2012209280A1 (en) 2013-08-15
EP2667713A1 (en) 2013-12-04
EP2667713A4 (en) 2014-09-10
BR102012001638A2 (pt) 2015-07-28
BR112013018942A8 (pt) 2018-07-31
EP2667713B1 (en) 2016-05-04
BR112013018942A2 (pt) 2018-05-22
CN103429082B (zh) 2015-05-06
BR102012001638A8 (pt) 2018-07-31
ZA201305579B (en) 2014-09-25
KR101542340B1 (ko) 2015-08-05
JP5739019B2 (ja) 2015-06-24
CO6731128A2 (es) 2013-08-15
KR101517313B1 (ko) 2015-05-04
PL2901857T3 (pl) 2017-08-31
HK1206938A1 (en) 2016-01-22
CA2825389C (en) 2015-12-22
US20120190858A1 (en) 2012-07-26
US20140046070A1 (en) 2014-02-13
MX339636B (es) 2016-06-01
WO2012103044A1 (en) 2012-08-02
KR20130121951A (ko) 2013-11-06
US9598368B2 (en) 2017-03-21
HK1187493A1 (en) 2014-04-11
JP2014511364A (ja) 2014-05-15
US8609853B2 (en) 2013-12-17
SG192579A1 (en) 2013-09-30
CA2825389A1 (en) 2012-08-02
UA105610C2 (uk) 2014-05-26
AR085023A1 (es) 2013-08-07
EP2901857A1 (en) 2015-08-05

Similar Documents

Publication Publication Date Title
MX342328B (es) Proceso para la preparacion de 4-amino-3-cloro-5-fluoro-6-picolina tos (sustituidos).
MX2013008604A (es) Proceso para la preparacion de 4-amino-3-cloro-5-fluoro-6-picolina tos (sustituidos).
AU2012209283A8 (en) Process for the preparation of 4-amino-5-fluoro-3-halo-6-(substituted)picolinates
MX2013008602A (es) Proceso para la preparacion de 4-amio-5-fluor-3-halo-6-picolinatos (substituido).
FI12004U1 (fi) Reaktiivinen ligniini
WO2012103279A3 (en) Methods and compositions for the synthesis of multimerizing agents
TN2013000411A1 (en) Branched 3-phenylpropionic acid derivatives and the use thereof
EP2671964A4 (en) High-strength cold-rolled steel sheet having excellent processability and high yield ratio, and method for producing same
IL223951A0 (en) (2-aryloxy- acetylamino) phenyl-propionic acid derivatives, method for producing same and use thereof as pharmaceuticals
PH12013500554A1 (en) Process for preparing pan-cdk inhibitors of the formula (i) and intermediates in the preparation
EP2670870A1 (en) Process for producing high strength steel, and to a steel produced thereby
MX2015007526A (es) Proceso para la preparacion de 4-amino-5-fluoro-3-cloro-6-picolina tos (sustituidos).
PT2686029T (pt) Método para fabricar, por um processo de sol-gel, cateteres incluindo revestimentos antibacterianos à base de ácido úsnico
MX2015007532A (es) Proceso para la preparacion de 4-amino-5-fluor-3-cloro-6-(sustitui do) picolinatos.
EP2673253A1 (en) A process for the production of (meth)acrylic acid and derivatives and polymers produced therefrom
GB2523674A (en) Compounds as inhibitor of DNA double-strand break repair, methods and applications thereof
HK1189124A (en) Process for the preparation of 4-amino-3-chloro-5-fluoro-6-(substituted)picolinates
EP2762464A4 (en) METHOD FOR THE PRODUCTION OF ACROLEINE, ACRYLIC ACID AND A DERIVATIVES THEREOF
MX2011012025A (es) Tintes azo acidos.
HK1189125A (en) Process for the preparation of 4-amino-5-fluoro-3-halo-6-(substituted)picolinates
MX366887B (es) Tetrahidrato de la sal de l-arginina del ácido s-(-)-9-fluoro-6,7-dihidro-8- (4-hidroxipiperidin-1-il) -5-metil-1-oxo-1h, 5h-benzo[i,j] quinolizin-2-carboxílico puro, y un proceso para su preparación.
WO2012021446A3 (en) Process for preparing aliskiren and its intermediates
PT2646516E (pt) Corantes ácidos isentos de metal, métodos para a sua produção e sua utilização
IN2013MU01952A (es)
AU2010905285A0 (en) Process for Producing Nitric Acid

Legal Events

Date Code Title Description
FG Grant or registration