Cyanoacetamide oxime

Within the past ten years, the market introduction of several new types of fungicides has significantly improved the prospects of controlling the Oomycetes. They belong to five different chemical classes the carbamates, the isoxazoles, the cyanoacetamide oximes, the etheyl phosphonates, and the acylalanines and related compounds. The chemical structures of those chemicals that have reached the commercial level are shown in Figures 3-5 (29, revised). Trade names, formulations and first reports are summarized in Table II (29, revised). The biological characteristics of these new fungicides and their impact on disease control have been reviewed by several authors (10, 16, 27, 28, 29, 33). 

The cyclization of a-hydrazono oximes (635) with orthocarboxylates is an excellent way of preparing 1,2,4-triazine 4-oxides (636) (73TL1429,7lLA(750)12,77LA1713). Using aldehydes or ketones instead of orthoesters provides 2,3-dihydro derivatives (637 Scheme 22) (75S794). Cyclization of a-hydrazonocarboxamides (638) with carbonic acid derivatives such as ethyl chloroformate affords l,2,4-triazine-3,5-diones (639) (68M1808). The a-hydrazonocarboxamides (638) can be prepared by the reaction of diazonium salts with a-activated acetamides such as cyanoacetamide as shown. 

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