Formamidine hydrochlorides, synthesis

Because formamidine hydrochloride is extremely deliquescent, considerable care must be exercised in its preparation if satisfactory results are to be achieved. Furthermore, formamidine hydrochloride cannot be used directly in most condensation reactions it must be treated first with a mole of base to liberate free formamidine. The same restriction applies to the metho-sulfate salt of formamidine in addition, complications in synthesis may be anticipated in this latter case because methyl hydrogen sulfate itself is an effective methylating agent.6... 

There are standard methods available for synthesis of amidines 10] and guanidines. In particular, reaction of an acylated thiourea with an amine, followed by removal of the acyl group(s) from the acylguanidine intermediate provides a mild and efficient synthesis [11]. When dihydroxyacetonc is treated with formamidine acetate in liquid ammonia, imidazole-4-methanol is isolated in 65-70% yield as its hydrochloride (3) (Scheme 4.3.2). This convenient synthesis is much less tedious than the old approach based on the reaction of fructose with ammonia [16]. 

Syntheses of the formamidine AdNHCH=NAd from 1-aminoadamantane hydrochloride (AdNH2,HCl) by reaction with s-triazene in pyridine and of the amide from p-(2-furyl)acrylie acid chloride and AdNH2 have been recorded the amide has antiviral activityReaction of 3-methylpentadienyl anion with adamantanone affords (668 75%) as the exclusive product the anion is a convenient reagent for the introduction of a 1,3-diene unit of the above type, and applications to terpene synthesis are discussed." Thermolyses of esters of P-hydroxyalkyltrimethylsilanes,... 

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