Diethyl phosphorocyanidate DEPC

One can also use diethyl phosphorocyanidate (DEPC) to effect a similar transformation. This was the reagent of choice in the generation of l-substituted-4-oxygenated-P-carbolines (49— 50). 

S)-2 are obtained by N-acylation using diethyl phosphorocyanidate (DEPC) (ref. 5), followed by hydrolysis. The results are summarized as follows. 

In addition to the most common methods for cyclization of linear peptides (vide supra), alternative coupling reagents have been used with varying success such as BOP-Cl, 140-142 norborn-5-ene-2,3-dicarboximido diphenyl phosphate (NDPP),119-143-144 pentafluorophenyl diphenylphosphinate (FDPP),1145-148 diethyl phosphorocyanidate (DEPC), 138-149 or T3P.197-1501... 

More than a decade ago, Yamada and coworkers [70] developed two efficient reagents, diphenylphosphoryl azide (DPPA) and diethyl phosphorocyanidate (DEPC), for peptide done construction. The exact mechanism still remains speculative. For example, in the case of DPPA, the intermediacy of the carboxylic acid azide is tentative, but it seems attractive to consider a concerted process as shown in Figure 2 [70 a]. 

Yamada S, Ikota N, Shioiri T. Diphenyl phosphorazidate (DPPA) and diethyl phosphorocyanidate (DEPC). Two new reagents for solid-phase peptide synthesis and their application to the synthesis of porcine motilin. J. Am. Chem. Soc. 1975 97 7174-7175. 

Shioiri, T., Yokoyama, Y, Kasai, Y, andYamada. S.. Phosphorus in organic synthesis. Part 11. Amino acids and peptides. Part 21. Reaction of diethyl phosphorocyanidate (DEPC) with carboxylic acids. A new synthesis of carboxylic esters and amides. Tetrahedron. 32. 2211. 1976. 

Harusawa, S., Hamada, Y, and Shioiri, T., Diethyl phosphorocyanidate (DEPC). A novel reagent for the classical Strecker s a-amino nitrile synthesis. Tetrahedron Ij- tt.. 20, 4663, 1979. 

One solution to this limitation was the introduction of cyanide sources that are soluble in organic solvents. The initial illustration used diethyl phosphorocyanidate (DEPC)6 for the conversion of 6 to a-aminonitrile 7. This stood in contrast to the classical Strecker reaction conditions which afforded no desired product. 

Later on, trimethylsilylcyanide and diethyl phosphorocyanidate (DEPC) were also found to activate the A -oxide in the above the Reissert-Henze reaction. In addition, lithium diethylphosphite was used as the nucleophile other than cyanide as shown in the transformation of N-methoxy pyridine 315 into the diethylphosphonate 316. ... 

In 1982, Hamada and Shioiri reported that carboxylic acids could be directly employed as acyl donors in the Schollkopf reaction via in situ activation (presumably via a mixed anhydride or azidocarbonyl species) using diphenyl phosphorazidate (DPPA). Thus reaction of a mixture of carboxylic acid, isocyanide, DPP A, and potassium carbonate in DMF afforded the anticipated oxazole product in good yield cf, 14 + 15 —> 16). Notably, this reaction was compatible with iV-protected a-amino acid starting materials and proceeded with minimal epimerization. Although diethyl phosphorocyanidate (DEPC) has found similar use in... 

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