SU406832A1 - METHOD OF OBTAINING ALKYLIDENIPYRANES OR SALTS OF PIRIL - Google Patents

Description

one

The invention relates to a new process for the preparation of alkylidene pyranes or pyryl salts of the formula I or II.

BI. / BgBj / BZ

SSN

B.A L ... 4

t © t

  Y ic

in which RI is a hydrogen atom or an alkyl;

R2 is an alkyl, aryl or heterocyclic residue or Ri and Na together are atoms supplementing a cycloalkyl ring;

Ra and Rg are phenyl unsubstituted or substituted by halogen atom;

R4 and Rs are hydrogen atoms or pairs of Rs-R4 and Rs-Re groups independently of one another — atoms that complement the benzene ring;

X is an oxygen, sulfur or selenium atom and Y is a mineral acid anion; which can be used in the synthesis of various practically important compounds, for example, pyrylocyanins - intensive dyes for film photographic materials.

A known method for the preparation of alkylidene pyranes or pyryl salts is that the pyrhenium salt, with free a- or position, is reacted with triphenylphosphine, the pyranyltriphenylphosphonium salt formed is reacted with phenyllithium; he was drunk in salt. The disadvantage of this method is

the laboriousness of the process associated with strong cooling and complex purification of the final product, and the insufficiently high yield of the target products is 30-40%. The purpose of the invention is to simplify the technology.

process and increase the yield of the target product.

A method for the preparation of alkylidene pyranes or pyryl salts of the formula I or II is proposed, which consists in that the salt of the pyryles of formula III

.

where Rs, Rt, RS, Re and X have the indicated values and Y is the anion of a mineral acid, is reacted with sodium 30 diethyl phosphite, the resulting pyranylphosphonate is reacted with potassium potassium butyl, the reaction mixture is reacted with a carbonyl compound of the formula IV RiR2CO where RI and Ra have the indicated meanings, and alkylidene diranes of formula I are isolated or do not convert it to the pyryl salt of formula II by the action of a mineral acid by conventional methods. The interaction proceeds according to the following scheme (oei:) 2 NaOPlOetJa V / T (2 o-p {oet) j J, HY. The method is universal and allows to enter into the reaction a wide variety of carbonyl compounds (aldehydes and ketones of the aliphatic, aromatic and heterocyclic series), and also to vary the salts of pyrily, benzopyryl, tiapirily, coantils and others over a wide range. The proposed method is fundamentally different from that known not only by the method of carrying out the reaction and the isolation of the obtained product, but also by the chemistry of the process, using other starting compounds, which reduces the number of process steps. The synthesis of alkylidene pyranes according to the proposed method proceeds without heating the reaction mixture (according to the known method, the reaction mixture is boiled in tetrahydrofuran to decompose intermediate betaine), which contributes to the purity of the target products, since it is at this stage that unstable unstable compounds are destroyed. The proposed method synthesizes a series of compounds that cannot be obtained by known methods or are obtained in insignificant yields. The final alkylidene derivatives of pyrans. benzopyrans, xanthenes, etc., and the pyrily salts derived from them are identified by elemental analysis, IR spectra, and some by counter synthesis. Example 1. 2,6-Diphenyl-4-benzylidene pyran In a three-necked flask equipped with a stirrer, a dropping funnel and a calcium chloride tube condenser, 0.3 g (0.013 mol) of sodium was dissolved in 70 ml of absolute ether with 2.1 g (0.015 g). mol) diethylphosphite. The mixture is stirred for 3-4 hours until the sodium is completely dissolved. Under vigorous stirring, 3.3 g of 2,6 diphenylpyrillium perchlorate are added to the obtained sodium salt of diethyl phosphite. The salt dissolves and a precipitate of sodium perchlorate appears. The reaction mixture was kept under stirring for 2 hours. The pyranylphosphonate obtained in the ether solution is mixed without isolation from 1.68 g (0.015 mol) of potassium greg-butylate in 100 ml of tetrahydrofuran in a four-necked flask with a stirrer, reflux condenser, funnel in a stream of dry nitrogen. The reaction mixture turns dark green. A solution of 1.1 g (0.01 mol) of benzaldehyde in 10 ml of tetrahydrofuran is immediately added. Immediately the dark green color disappears and the solution becomes yellow. The mixture is stirred for 1 hour, treated with water, the organic layer is separated, washed twice with water, the aqueous layer is extracted twice with ether. The solvent is removed from the organic extract and the resulting benzylidene pyran is crystallized from alcohol and heptane. Yield 2.4 g (66%), t. square 140 ° C. Paideno,%: C 89.54; H 5.76. C24Hi8O. Calculated,%: C 89.44; H 5.59. The alkylidene pyran is dissolved in a minimal amount of alcohol and 1 ml of concentrated perchloric acid is added dropwise. A yellow precipitate of the pyrilic salt precipitates. The output is quantitative. The resulting 2,6-diphenyl-4-benzylnirylperchlorate has an mp. 219 ° С (from acetic acid), alkylidene pyranes and correspondingly substituted pyrylium salts with veratraldehyde (55%), with benzophenone (64%), with 2,4-methoxybenzaldehyde (50%), l-nitrobenzaldehyde (49%), acetophenone (50%), l-nitrobenzaldehyde (49%), acetophenone (50%), l-nitrobenzaldehyde (49%), acetophenone (46%), dibenzylketone (30%), etc. Alkylidenepyranes with acetophenone, dibenzylketone cannot be isolated by the Wittig reaction, and the yield is two times lower with acetophenone. Example 2. 2,6-Diphenyl-4- (diphenylmethylene) -pyrane To sodium salt of diethylphosphite (from 0.3 g of sodium and 2.1 g of diethylphosphite) add 3.3 g (0.03 mol) ac to 100 ml of absolute ether 2,6-diphenylpyrillium perchlorate salt. The reaction mixture is stirred until the suspension of the pyryl salt disappears (2 hours). The pyranyl phosphonate ethereal ethereal solution obtained is poured into a suspension of 1.68 g (0.015 mol) of potassium ret-butoxide in 100 ml of tetrahydrofuane under a stream of dry nitrogen with stirring. The reaction mixture turns dark green. A solution of 2.1 g of 0.011 mol of benzophenone in 20 ml of tetrahydrouran is immediately added. The solution becomes yellow. the mixture is stirred for 2-3 hours and set overnight. After treatment with water or56

The lathic layer is separated, washed two times. In a similar way, arylidene- {alkylidees are prepared with water and dried. The solvent, idene) -pyranes on the basis of the 2,6-diphenylpyrillium, was removed, the product obtained was crystallized from alcohol-perchlorate into carbonyl-containing compounds of heptane, yield 65%, mp. 200 ° C. Listed in Table. 1. Alkylidene- (arylidene) based on pyrylium salts and carbonyl-containing compounds

Table 1

 Found,%: S 9.74. Calculated,%: .S 9.37. Found,%: N 3.85, Calculated,%: N 3.7. Found,%: N 3.82. Calculated,%: N 3.75. 7 Example 3. 2-Phenyl-4-benzylidene-5,6-benzopyran 2.1 g (0.01 mol) of 2-phenyl-5,6-benzopyryl perchlorate are powdered with stirring to the sodium salt of diethyl phosphite (from 0.3 g sodium and 2.1 g of diethylphosphite) in ethereal solution. After the suspension of the pyrylium salt disappears, the resulting phosphonate solution is added to 1.68 g (0.015 mol) of potassium greg-butylate.

Pyrillium salt.j,

 Found,%: S 7.24. Calculated,%: S 7.50.

 Found %: N 3.34. Calculated. %: N 3.40.

 Found %: N 2.84. Calculated. %: N 2.95.

8 in 100 ml of tetrahydrofuran in a stream of dry nitrogen. The solution acquires a bright red color, which, with the addition of 1.1 g (0.01 mol) of benzaldehyde, turns yellow. After a brief stirring, the reaction mixture is treated with water, the organic layer is separated, washed with water and dried. After removal of the solvent, the product is crystallized from alcohol, yield 58%, so pl. 87 ° C. table 2

Similarly, 2,6-di-g-bromophenyl-4-benzylidene pyran is obtained, yield 56.0%, mp. 198 ° C; 9-benzylidenexanten, yield 61%, so pl. 115 ° C; 2,6-diphenyl-4-benzylidentiapiran, yield

53.4% |, t. Pl. 139 ° C; 2,6-diphenyl-4-benzylidenese-pyran, yield 53.4%, so pl. 140 ° C.

Example 4. 2,6-Diphenyl-4-benzylselenapyrylperchlorate

1 g (0.0025 mol) of 2,6-diphenyl-4-benzylidenelenepyranpiran is dissolved in a minimum amount of glacial acetic acid and a few drops of 70% perchloric acid are added. Yellow crystals of 2,6-diphenyl-4-benzyl selenipirilium perchlorate precipitate, which crystallize from glacial acetic acid and nitromethane.

The output is almost quantitative.

Pyrillium salts listed in Table. 2, receive almost quantitative yield, as described in example 4.

Subject invention

The method of producing alkylidene pyranes or pyryl salts of the formula I or II

Ix

sn

Is v s1 © 1

Ibva bz y

- WITH

in which RI is a hydrogen atom or an alkyl;

R2 is an alkyl, aryl or heterocyclic residue or RI and Ra together are atoms, in addition to a cycloalkyl ring;

Rs and Re are phenyl unsubstituted or substituted by halogen atom;

R4 and Rs are a hydrogen atom or pairs of groups Rs-R4 and R5-Re independently of each other are atoms that supplement the benzene ring;

X-atom of oxygen, sulfur, or selenium, and Y- is the anion of mineral acid,

characterized in that, in order to simplify the process technology and increase the yield of the target product, the pyryl salt of the formula HI

where Ra, R4, RS, Re and X have the indicated ziacheni and Y is the anion of mineral acid,

reacted with the sodium salt of diethylphosphite, the pyranylphosphonate formed is reacted with potassium t-butylate, the reaction mixture is reacted with a carbonyl compound of the formula IV RiRsCO,

where RI and R2 are as defined,

and alkylidene pyran of formula I is isolated or its pyryl salt of formula II is converted by the action of a mineral acid by conventional methods.