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Recherches sur la formation et la transformation des esters LXXIX [1]. Sur la réaction de l′isothiocyanate d′o‐méthoxycarbonyl‐phényle avec divers acides et l′acide sérinephosphorique
Author(s) -
Cherbuliez Emile,
Espejo O.,
Willhalm B.,
Rabinowitz J.
Publication year - 1968
Publication title -
helvetica chimica acta
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.74
H-Index - 82
eISSN - 1522-2675
pISSN - 0018-019X
DOI - 10.1002/hlca.19680510129
Subject(s) - chemistry , medicinal chemistry , phenyl isothiocyanate , stereochemistry , leaving group , serine , nucleophile , isothiocyanate , cysteine , catalysis , organic chemistry , enzyme
Amino acids devoid of «leaving groups» on their β carbon atom (neither OH: serine, nor SH: cysteine) react with o ‐methoxycarbonyl‐phenyl isothiocyanate (I) in the presence of one equivalent of NaOH, in water‐dioxane or in ethanol, to yield the corresponding hydroquinazolinone derivatives II which were isolated as free acids. When treated with CH 3 COOH + conc. HCl the hydroquinazolinone resulting from the reaction of L ‐serine with I undergoes a nucleophilic attack of the carbon bearing the leaving group OH by a lone pair of electrons of S; this attack produces the formation of an additional thiazolidine ring, yielding the thiazoloquinazolinone derivative (−)‐III. In an analogous reaction DL ‐serine phosphoric acid treated with I at pH 8–9 yields the corresponding substituted hydroquinazolinone which, boiled in 1 N hydrochloric acid, undergoes ring closure to (±)‐III by the same mechanism as the serine derivative (leaving group: OPO 3 H 2 ). L ‐Cysteine reacted with 2 equiv. of I and then treated with CH 3 COOH + conc. HCl gives two products: (−)‐III produced by the same mechanism as for serine (leaving group: SH), and the quinazolinone derivative IV where the SH group is also thiocarbamoylated.