DD252189A1 - PROCESS FOR THE PREPARATION OF 7,8,9,10-TETRAHYDRO-PYRIMIDO (4,5-C) ISOCHINOLINE-1,6 (24, 5H) -dione - Google Patents

Abstract

3-Amino-1,2,3,6,7,8-hexahydro-1-oxo-isoquinoline-4-carboxylic acid amides, trialkyl orthoformate, ethoxymethylenemalononitrile, ethyl ethoxymethylenecynecetate, 7,8,9,10-tetrahydropyrimido (4,5-) c) -diones isoquinoline-1,6 (2H, 5H). Process for the preparation of 7,8,9,10-tetrahydro-pyrimido (4,5-c) isoquinoline-1,6 (2H, 5H) -dione. According to the invention, a 3-amino-1,2,5,6,7,8-hexahydro-1-oxo-isoquinoline-4-carboxylic acid amide of the general formula I in solution or suspension with a methine-yielding condensing agent is added to a compound of the general formula (II) Formula II implemented. Among the compounds of general formula II are fungicidally active substances. Formulas I and II

Description

For this 1 page formulas

Field of application of the invention

The invention relates to a process for the preparation of 7,8,9,10-tetrahydro-pyrimide [4,5-c] isoquinoline-1,6 (2H, 5H) -diones of the general formula II.

The invention is of interest for agriculture, horticulture and forestry, where inventively prepared compounds z. B. are used as fungicides.

Characteristic of the Prior Art

Cyclization reactions of o-amino-carboxylic acid amides with orthoformic acid esters to various pyrimido-fused ring systems are known (W.L.F. Armarego: "The Chemistry of Heterocyclic Compounds", 24th volume "Fused Pyrimidines, Qinazolines", New York, London, Sydney 1967).

A 5-phenyl-7,8,9,10-tetrahydro-pyrimido [4,5-c] isoquinoline-1,6 (2H) -dione was prepared by cyclization of 3-ampho-5,6,7,8-tetrahydro 1-oxo-2-phenylisoquinoline-4-carboxylic acid amide with triethyl orthoformate and acetic anhydride (K. Gewald, H. Schäfer, P. Bellmann, J. prakt. Chem. 324, 933 (1982)). 9,10-Tetrahydro-pyrimido [4,5-c] isoquinoline-1,6 (2H, 5H) -diones of the general formula II are hitherto unknown.

Object of the invention

The aim of the invention is to provide new, biologically active, hydrogenated Pyrimidoisochinolindione the practice as active ingredients available.

Explanation of the essence of the invention

The object of the invention is to develop a process for the preparation of 7,8,9,10-tetrahydro-pyrimido [4,5-c] isoquinoline-1,6 (2H, 5H) -diones of general formula II.

According to the invention an S-amino-i ^^^^^ - hexahydro-i-oxo-isoquinoline ^ -carboxamide of the general formula I in solution or in suspension with a methine-supplying condensing agent is reacted with heating to give a compound of general formula II.

In general formulas I and II, R ^{1 is} H, alkyl (optionally substituted) or phenyl (optionally substituted).

The compounds prepared according to the invention can also be present in the general formula II tautomeric forms.

The reaction is generally carried out at temperatures between 50 and 200 ⁰ C.

Suitable condensing agents which give methine groups for the preparation of the compounds of general formula II are, for example, ethoxymethylenemalononitrile or ethoxymethylehcyaneacetic acid ethyl ester, but in particular orthoformic acid trialkylester. It is convenient to separate most of the resulting alcohol during the reaction.

For large reaction mixtures should for good mixing, eg. B. by stirring, are taken care of.

The process according to the invention makes it possible for the first time to prepare the compounds of the general formula II.

The compounds of general formula II are biologically active. Among them are those which have a fungicidal action.

The invention will be explained below by embodiments.

embodiments

example 1

200 mg of 3-amino-1,2,5,6,7,8-hexahydro-1-oxo-isoquinoline-4-carboxamide (I: R '= H) are refluxed with 20 ml of triethyl orthoformate for 8 hours. After distilling off low-boiling fractions in a distillation apparatus is refluxed for a further 6 hours. The unreacted orthoformate is distilled off in vacuo and the residue recrystallized. M.p .:> 36O ⁰ C, yield: 110 mg (52% of theory) of 7,8,9,10-tetrahydropyrimido [4,5-c] isoquinoline-1,6 (2H, 5H) - dione (II: R ¹ = H).

CONHR

25 8.86-369551

Claims (2)

1. A process for preparing 7,8,9,10-tetrahydropyrimido [4,5-c] isoquinoline-1 _/ 6 (2H, 5H) -diones of the general formula II, characterized in that an S-amino-I ^^^ J ^ -hexahydro-i-oxo-isoquinoline ^ -carboxamide of the formula I in solution or suspension with a methine supplying condensing agent are reacted under heat, wherein in the general formulas I and II R ¹ is (H, alkyl optionally substituted ) or phenyl (optionally substituted). 2. The method according to claim 1, characterized in that is used as a condensing agent ethoxymethylenemalononitrile, Ethoxymethylencyanessigsäureethylester or Orthoameisensäuretrialkylester.