Hydantoin Hydrazones

The oxidation of phenylhydrazine and 1,2-disubstituted hydrazines to hydrazones and diazenes by CI2C proceeds via formation of unstable azomethine imines.95 The conversion of alcohols into alkyl halides is achieved by reaction with CCI4 (or CBr4) in DMF under electrochemical reduction.96 The reaction of dihalocarbene X2C with DMF to form a Vilsmaier reagent (93) is proposed as the key process. The reaction of simple isocyanates (RNCO) with dimethoxycarbene normally gives hydantoin-type products. In the reaction with vinyhsocyanates such as (94), however, hydroindoles (95) are formed in good yields.97... 

Maeda and Yoshida 238, 239) by hydroformylation of acrolein obtained l,l-diacetoxy-4,4-dialkoxybutane (17), which by Buecherer s reaction gave (3-(hydanto-5-yl-)propionaldehyde acetal (18). The phenyl-hydrazone of (18), by the Fischer indole synthesis, gave tryptophan hydantoin (20). Attempts to obtain crystalline (20) were unsuccessful,... 

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