CS203002B2 - Process for preparing alpha-diol-gamma-dioxocompounds - Google Patents

Abstract

1505667 Diol-diones SNAMPROGETTI SpA 12 June 1975 [12 June 1974] 25278/75 Heading C2C Compounds of formula where R<SP>1</SP>, R<SP>2</SP>, R<SP>3</SP> and R<SP>4</SP> are hydrocarbyl or hydrogen, are prepared by oxidizing with an oxidizing system comprising osmium tetroxide and an alkali or alkaline earth metal chlorate. Water or an organic solvent may be used. Osmium tetroxide may be recovered by flushing with an inert gas and trapping in a quantity of the starting material or by solvent extraction followed by addition of starting material to the extract and evaporation of the solvent. An example prepares erythro-3,4- dihydroxy-hexan-2,5-dione. Reference has been directed by the Comptroller to Specification 1,188,886.

Description

The invention relates to a process for the preparation of α-diol-γ-dioxo compounds, which are important synthesis intermediates, for example in the preparation of furan derivatives by cyclization, some of which may be used as aromatizing agents [see, for example, G. Budhi, E. D emile and F. Thoma, J. Org. Chem. 38, 123 (1973) and L. Re, B. Mauin, G. Ohlaff, Helv. 56, 1882/1973/3.

U.S. Pat. No. 3,576,014 to Examples 1a and 1b describes the production of dioldions starting from 1-bu ul-Jou followed by oxidation using the system C. The process consists of two reactions, each of which requires washing, separation and purification stage.

The invention relates to a process consisting of ring opening of an edge derivative by means of a single oxidation step. .

SUMMARY OF THE INVENTION The present invention relates to a process for the preparation of di-p1-dioxo compounds of formula (I):

R ¹ - co - C - C - CO-R ^4/1 /

OH OH

Wherein R ¹ , R ^x , R ^J and R are the same or different are a α 1 -rene / hydrogen atom or a C 1 -C 4 alkyl group, characterized in that 1 mole of the compound of formula (II),

R ² R 3

wherein ^R 1, R ² , R ⁴ and R 6 are as defined above, reacted in the presence of water, optionally with the addition of an inert solvent, of tetrahydrofuran, C 1 -C 3 alcohols, carbon tetrachloride, diethyl ether and benzene with 0.02 to 0.2 moles of osmium tetroxide and 1 to 5 moles of alkali metal or alkaline earth metal chlorate at a temperature of 25 to 50 ° C and under pressure to maintain the reaction system in the liquid phase.

In the process of the invention, the oxidizing agent is osmium tetroxide, but may be used in catalytic amounts (preferably at least 20 mg per gram of substrate). The osmium tetroxide is continuously regenerated from the chlorate by oxidative cleavage of the adduct to osmium oxide and the substrate. The chlorate must therefore be broken at least in the stecha. ome three. ronnshjsví. In addition to this, the oscillator may be regenerated at the end of the reaction either by trapping the oxides of oxygen in a stream of nitrogen in a precipitator containing the starting product to form a nonvolatile adduct, or by selective extraction of the rotary oxide with a suitable solvent (CCl3, benzene, Et2O). by evaporation of the solvent after the addition of the starting compounds, if appropriate in a manner known per se.

The reaction is carried out in aqueous medium. When using solid insoluble materials, it is preferable to add an inert solvent, either mixed with water and different. At least partially the sub-substrate (THF, alcohols), or with water, is non-soluble and soluble in the sub-substrate and the oxide. os ^ m i. ‘ei <. ´ <C 1 .., i · t, benzene.

In comparison with known in the production field, n < The invention is advantageous in view of the lower grinding forces of 1 to ¹ and the fact that it is carried out at temperature. even in shorter responses to the times j reaches higher or higher; yields.

In addition, in the preparation of the uranium derivatives, the quench is mentioned. z η i the method c-diol-y * -doxo s L o t i n i n especially interesting, iiii-o i i. As described above, for example, the aforementioned G. Buchl et al., Aqueous at the end of the reaction; mixtures after r c y. e n e r a c i k i s of the octagon, without isolation between the products.

The invention will now be described in more detail by way of example, but without limiting the spirit of the invention.

For example

Preparation of erythro-3,4-dihydroxyhexane-2,5-dione from 2,5-dimethylaminofuran.

To 30 ml of water was added 2.8 g (22.8 mole) of potassium phosphate, 50.8 mg (0.20 mmoO) with cheesecloth and 0.96 g (10.0 οΟ) The mixture was stirred for 17 hours at room temperature in a sealed vessel. The dioethyl / furanate phase, which was not dissolved in water, was transferred to the reaction mixture.

Regeneration of the carbon monoxide can be effected by bubbling a stream of nitrogen after the reaction has ended with the reaction vessel connected in the outlet to a trap provided with a porous whisper immersed in dimethylfuran and cooled. According to this procedure, the oesium oxide was captured through a non-volatile dioe thyrofuran adduct. The content of the trap may be deserts after the addition of water and potassium chlorate in the following process.

Alternatively, the regeneration may be carbon <? Smičelého performed using the selective extraction of action of _CCI-t, followed by the addition of g lmeChу 1fи аnи г к extract / thereby forming the adduct / solvent and distillation; the distillation residue can be used in the following procedure after the addition of water and potassium chlorate.

The reaction mixture was evaporated to dryness under 2 kPa vacuum at room temperature, the residue was extracted several times with ethyl acetate, and the combined extracts were dried (over anhydrous sodium sulfate) and evaporated to dryness in vacuo.

The above procedure was obtained 1.26 g oílého crystalline product, mp ^{46-49: C,} which was obtained from 0.89 g / yield 61 / pure eг уtro - 3,4 "dihydro hexane-2,5-dione , by crystallization from chloroform-ligroin. The compound showed a melting point of 60-62 ° C, with the infrared and NMR spectra consistent with the assumed analysis. Buchl et al.

SUBJECT OF THE INVENTION

Way production n-diol-N-dioxoside formula I, R ² R ³ J ¹ , I R - CO - C - C - CO - R I 1 / 1 / 1 1 01: 011 к t i · Г .. *, T ’ ! , К i í <js: j ·! <t. be different a means «. ui? or alkyl with from 1 to 4 carbon atoms atoms, ;; '-i' · '. · -,  · .; S>. ¹ !?. 1 S i ν ·; ^; li: ohe (. η é ' 1 1.

Claims (1)

SUBJECT OF THE INVENTION Way production n-diol-N-dioxoside formula I, R ² R ³ J ¹ , I R - CO - C - C - CO - R I 1 / 1 / 1 1 01: 011 к t i · Г .. *, T ’ ! , К i í <js: j ·! <t. be different a means «. ui? or alkyl with from 1 to 4 carbon atoms atoms, ;; '-i' · '. · -,  · .; S>. ¹ !?. 1 S i ν ·; ^; li: ohe (. η é ' 1 1. i o) ... in R, R ", R n: <» *.) and in ’... n: in, a · c · h a re a g o v a t in the presence of! >, ;; <·; i μ ad é with the addition of inert solvents l.a / e ski; p. и у t <? t r and h o r o r u r a nu, alcohol s i! at?: .`- ii i <· ..ι. t 'trichloromethane than, diethyl ether and benzene, with 0, 0 11 .i ?. 0.2 moles of oxide of s;>; The alkali metal hypochlorite or κ7 ((and alkaline earth from; temperature up to?) and under pressure to maintain the reaction system in the liquid phase. Srverogran .. n. Mo »t