Cyanogen chloride adducts

Some additional examples are given in Scheme 8.6. The electrophiles that have been used successfully include iodine (Entries 2 and 3) and cyanogen chloride (Entry 4). The adducts can undergo conjugate addition (Entry 5), alkylation (Entry 6), or epoxide ring opening (Entries 7 and 8). The latter reaction is an early step of a synthesis of epothilone B. 

CCINI cyanogen chloride 506-77-4 -7.00 1.4446 2 314 CH6N203 hydrogen peroxtde-urea adduct 124-43-6 25,00 1.2346 2... 

Chlorosulfonyl isocyanate6 (CSI) (57) is a very reactive compound which was first prepared from cyanogen chloride (56) and sulfur trioxide (Graf, 1956) (Scheme 31). CSI (57) undergoes [2+2] cycloaddition reactions with various alkenes initial adducts like (58) and (59) may be hydrolysed to the b-lactams (60) and (61). The cycloaddition reaction also occurs with enamines (62) to give products like (63) and (64) (Scheme 32). 

Interest in cyanogen bromide as a brominating agent for imidazoles has been rekindled. It seems that bromo products can be made in this way, for example, 1-benzylimidazole reacts with cyanogen bromide in the presence of 4-dimethylaminopyridine to give l-benzyl-2-bromoimidazole, perhaps via an ylide mechanism. Cyanogen chloride and the pre-formed adduct of cyanogen bromide and... 

Acylation with phosgene occurs under very mild conditions to give enamino-acyl chlorides which undergo solvolysis to esters or amides (Scheme 93). Cyanogen chloride reacts with enamines to give cyanoenamines and a-cyanoketones on hydrolysis. Cyanogen bromide and iodide react differently a 1 1 adduct is formed which, on hydrolysis, leads to 2-haloketone (Scheme 94). 

Piperazine reacts with benzyl chloroformate to give l-(benzyloxycarbonyl)-piperazine (1690), with benzyl chloride (1 mol) (and piperazine dihydrochloride) to 1 -benzylpiperazine (1691-1693), with ethyl chloroformate and sodium hydroxide to 1,4-diethoxycarbonylpiperazine, which with sodium benzyl oxide gave 1,4-dibenzyloxycarbonylpiperazine (1694), and with cyanogen to 1,4-bis(C-cyano-C-iminomethyl)piperazine (139) (1695). The piperazine-chlorotrimethylsilane adduct with triethylamine gave l,4-bis(trimethylsilyl)piperazine (1696), and piperazine in... 

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