Ferrocenyl alkylation of 4‐mercapto derivatives of sydnones and sydnone imines. New antidotes for sulfonylurea herbicides

Abstract

The first representatives of ferrocenes containing mesoionic heterocyclic substituents were obtained by the ferrocenyl alkylation of 4-mercapto derivatives of sydnones and sydnone imines. Several synthesized derivatives showed high antidote activity against metsulfuron-methyl (Zinger WP) herbicide.

Plant growth‐regulating activity of α‐([sydnon‐ and sydnone imin]‐4‐yl‐thio)acetylferrocenes

“…The geometry of the 4‐thiosydnonyl fragment in compound 4b almost completely coincides with that one in the similar 4‐thio‐3‐phenylsydnone derivative described earlier 33 . The interatomic distances and bond angles of the α‐thioacetylferrocene fragment are close to the corresponding values in acetylferrocene 38 …”

“…The geometry of the 4-thiosydnonyl fragment in compound 4b almost completely coincides with that one in the similar 4-thio-3-phenylsydnone derivative described earlier. 33 The interatomic distances and bond angles of the α-thioacetylferrocene fragment are close to the corresponding values in acetylferrocene. 38 S C H E M E 1 Synthesis of the α-(sydnon-4-ylthio)acetylferrocenes 4a-d. Sydnone imines 5, as well as sydnones, form the lithium 4-thiolates 6 upon sequential treatment with n-BuLi and elemental sulfur 39 (Scheme 2).…”

“…We have previously shown that a number of the ferrocene derivatives containing the heterocyclic (including mesoionic sydnone and sydnone imine) substituents exhibit growth-regulating and herbicide antidote activities. 18,[33][34][35] The obtained ferrocenyl derivatives 4a-d and 7a-k were studied for the growth-stimulating and antidote activities against the sulfonylurea herbicide in vegetation experiments on corn seedlings.…”

“…[30][31][32] The ferrocene derivatives containing the mesoionic (sydnonе and sydnonе imine) substituents exhibit growth-regulating and herbicide antidote activities. [33][34][35] The purpose of this study was to develop the method for the synthesis of α-thio-substituted acetylferrocenes containing the mesoionic heterocyclic substituent (sydnone or sydnone imine) at the sulfur atom. A study of their growth-regulating properties and the antidote activity against herbicide Metsulfuron-Methyl (Zinger WP) was also carried out in vegetation experiments on corn seedlings.…”

“…Despite the fact that they are not found in living nature, a large number of the substances exhibiting a wide range of the biological activity have been found among them 30–32 . The ferrocene derivatives containing the mesoionic (sydnonе and sydnonе imine) substituents exhibit growth‐regulating and herbicide antidote activities 33–35 …”