DD148778A1 - PROCESS FOR PREPARING PYRAZOLE OXAZINES - Google Patents

Abstract

The aim of the invention is to develop a process for the preparation of 1-acyl-4-alkoxy-3-methylthio-6H-pyrazolo & 3,4-d! & 1,3! Oxazin-6-ones. The pyrazolooxazines of the general formula III where R is an alkyl group and R (exp1) is an optionally alkyl-, alkozy- or halogen-substituted phenyl or benzyl radical can be prepared by reaction d. Pyrazoline derivatives of the general formula I, in which R and R (exp1) have the above meaning, with isocyanates of the general formula II in which R & exp2! represents an optionally alkyl-, alkoxy- or halogen-substituted phenyl radical, are prepared. These pyrazolooxazines can be used as organic intermediates for further syntheses. They are particularly suitable as starting materials for the preparation of other heterocyclic derivatives.

Description

Process for the preparation of pyrazolooxazines Field of application of the invention

The invention relates to a process for the preparation of i-acyl-alkoxy-S-methylthio-eH-pyrazolo | j5,4-d 'JJJ> 3Joxazine-6-ol ·

These pyrazolinooxazines can be used as organic intermediates for further syntheses. They are particularly suitable as starting materials for the preparation of further heterocyclic derivatives.

Characteristic of the known technical solutions

i-Acyl-alkoxy-1-methylthio-1-yl-pyrazolo [3,4-d] JJ, 3J oxazin-6-ones are not yet known

Object of the invention

The aim of the invention is to develop a process for the preparation of i-acyl-alkoxy-methylthio-oH-pyrazolo [3,3-d] [i, 3-jaxazin-6-ones.

Loan of the essence of the invention

The pyrazolinooxazines of general formula III where R is an alkyl group and R is an optionally alkyl-, alkoxy- or halogen-substituted phenyl or benzyl radical can be prepared by reacting the pyrazoline

derivatives of general formula I in which R and R are the

2 eat 620

have the above meaning, with isocyanates of the general

2 my formula II in which R is an optionally alkyl, alkoxy or halogen-substituted phenyl radical are prepared.

The reactions are carried out in an organic solvent in the presence of an organic base. Pyridine is particularly suitable as the reaction medium. The reaction times are from 60 to 120 ^° C. The reaction times are from 2 to 10 hours. After the reaction and cooling to 5 ^° C., the precipitate formed is filtered off. Further product can be obtained from the mother liquor by concentration in vacuo. The crude products can be purified by recrystallization from organic solvents.

embodiments Embodiment 1

1 - (p-Anisoyl) -4-methoxy-3-methylthio-6H-pyrazolo [3,4-d

0.01 mol of 1- (p-anisoyl) -5-imino-3-methylthio-A ³ -pyrazolin-4-carboxylic acid methyl ester is dissolved in 30 ml of anhydrous pyridine with warming · After the dropwise addition of 0.015 mol of phenyl isocyanate is heated Solution for 4 hours on the water bath and then allowed to cool to 5 ⁰ C. It is filtered off, and won by concentration of the mother liquor in vacuo more product. The combined crude products are crystallized from dimethylsulfoxide to «yield: 83 $ d.Th. Melting point: from 288 ^° C.

decomposition

Embodiment 2

1-benzoyl-4-metoxy-3-methylethyl-6H-pyrazolo [j5, 4-d]], 3joxazin-6-one

From 0.01 mol of 1-benzoyl-5-imino-3-raethylthio ^ ^5- pyrazoline-4-carboxylic acid methyl ester and 0.015 mol of p-chloro-phenyl isocyanate, as described in Example 1.

Yield: 71 $ d.Ttu Melting point: from 244 ⁰ C

Decomposition Example 3

Ί- (p-chlorobenzoyl) -4-methoxy-3-methylthio-6H-pyrazolo, 3] oxazin-6-one

From 0.01 mol of 1- (p-chlorobenzoyl) -5-imino-3-methylthio-Δ-pyrazolin ^ -carboxylic acid methyl ester and 0.015 mol of phenyl isocyanate, as described in Example 1

Yield: 65 $ d.Th · Melting point: from 285 ⁰ C

decomposition

Ausführungsbei game 4

1- (p -anisoyl) -4-ethoxy-3-methylthio-6H-pyrazolo [3,4-d] (3,3,3oxazin-6-one

From 0.01 mol of 1 ~ (p-anisoyl) -5-iraino-3-methylthio-A ' ⁵ -pyrazolin-4-carboxylic acid ethyl ester and 0.015 mol of phenyl isocyanate, as described in Example 1. The crude products are recrystallized from chloroform / ethanol.

Yield: 74% d.Th "Melting point: 250-254 ⁰ C.

decomposition

" * " 2 18 620

Embodiment 5

i-Benzoyl-ethoxy-methylthio-O-H-pyrazolo [p, 4-d] -jl, 3-oxazin-6-one

From 0.01 mole of i-benzoyl-S-imino-J-methyl-tiio- [Delta] - zolin-1-carboxylic acid ethyl ester and 0.015 mole of p-chlorophenyl isocyanate, as described in Example 1 »

Yield: 62s6-d.Ttu Melting point: 268-272 ⁰ C.

decomposition

Embodiment 6

4-Ethoxy-3-ethylthio-1-phenylacetyl-6H-pyrazolo [3,4-d] [i, 5-jaxazin-6-one

From 0.01 mol of 5-iralno-3-methylthio-1-phenylacetyl ~ A ³ -pyrazoline-4-carboxylic acid ethyl ester and 0.015 mol of phenyl isocyanate, as described in Example 1. Yield: 58 $ d.Ttu Melting point: from 246 ⁰ C

decomposition

For this d page formulas

218 620 - '

ROOC-C = C-SCH

HN = C NH

C = OH ^R

II

• I

OR 4.

O ^ C -C -CH-

C = EAR ¹

III

Claims (1)

Inventions claim Process for the preparation of pyrazolooxazines of the general formula III in which R is an alkyl group and R is an optionally alkyl-, alkoxy- or halogen-substituted phenyl or benzyl radical, characterized in that pyrazoline derivatives of the general formula I in which R and R have the above meaning, with isocyanates of the general formula II in which R is a is optionally alkyl-, alkoxy- or halogen-substituted phenyl radical.