Methylhydrazine, cleavage

Before the advent of enediyne antitumor antibiotics, there had been few examples of carbon radicals believed to mediate DNA cleavage. The simplest of all, the methyl radical has been shown to effect DNA cleavage under enzymatic as well as chemical conditions [24]. Oxidation of methylhydrazine by horseradish peroxidase or ferricyanide (Fig. 5) gave high yields of methyl radicals, which were shown to cleave DNA by purine ring alkylation. 

Mixtures of the isomers (243) and (244) react with hydrazine hydrate to give the products (245) and (246) (Equation (34)) <84EUP108382> and the aza derivatives (247). Methylhydrazine gave the amines (248) (Equation (35)) <84JHC965>. Alkaline cleavage of compound (249) followed by treatment with hydrazine gave compounds (250) and (251) (Equation (36)) <81ACH167>. 

The ene hydrazine 100, prepared from dimedone and methylhydrazine, forms the Michael adduct 101 with dimethyl acetylenedicarboxylate. The adduct is converted into a mixture of pyrrole and pyridone derivatives, 103 and 104, in boiling tetralin. These products arise by a [3.3]sigmatropic shift in the adduct with cleavage of the nitrogen-nitrogen bond to give 102, followed by cyclization and elimination of ammonia and methanol, respectively (equation 42)63. 

Acyl-oxygen cleavage of the serine 3-1 ictone, although not desired in most cases, has been employed for the synthesis of (S)-2-methyl-4-benzyloxycarbonylaminopyrazolidine (10). Methylhydrazine in dichloromethane adds regioselectively to the carbonyl group of (1) to afford the hydrazide (9), which after several steps affords (10) (eq 5). ... 

Synthetic strategy Methylhydrazine-mediated aerobic oxidative cleavage of aiylboronic acids to phenols Catalyst Air... 

Keywords Arylboronic acids, methylhydrazine, tetrahydrofuran, air, room temperature, aerobic oxidative C-B bond cleavage, phenols... 

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