Studies of nitriles. VII. Synthesis and properties of 2-amino-3,3-dichloroacrylonitrile (ADAN).

2-Amino-3, 3-dichloroacrylonitrile (ADAN), a versatile polyfunctional synthetic intermediate, was prepared in 96% yield by addition of HCN to the C-N triple bond of dichloroacetonitrile (11a). The structural proof for ADAN, an enamino nitrile, comes from comparison of the spectral data with those of 2-imino-3, 3, 3-trichloropropionitrile (15), a model compound for α-imino nitrile. Similarly, 2-amino-3, 3-dibromoacrylonitrile (13) was prepared from dibromoacetonitrile (11b) and HCN in 82% yield. ADAN, although relatively unstable in air at room temperature, can be stored without detectable change for a long period in nitrogen or ether vapor atmosphere at low temperatures. 2-Amino-3, 3-bis (substituted mercapto) acrylonitriles (18a-c), mercapto-analogues of ADAN, were prepared from ADAN or its N-acyl derivatives (16, 19) by nucleophilic substitution of the chlorine atoms with mercaptides, and in the latter case, with subsequent hydrolysis of the N-acyl group. Hydrolysis of the cyano group of N-acyl derivatives (16, 21, 22) gave the corresponding carboxamides (23), carboxylic acids (24), and N-t-butylcarboxamides (26) in good yields.