Compounds for pH-controlled release of hydrogen sulfide
The embodiments herein generally relates to compounds and methods for releasing H 2 S in a pH dependent manner. In particular, the invention provides compounds of various formulations which release H 2 S in a controlled, predictable and sustained manner upon contact with an aqueous environment, such as the circulatory system of an animal, and which are thus suitable for in vivo delivery of H 2 S.
1. A compound having the formula
wherein
R1 is aryl, alkyl, aralkyl, and substituted aryl or a combination thereof;
R2 is a hydrogen, or a part of a 3 to 7 membered ring system connecting R2 to R3;
R3 is a hydrogen, or part of the 3 to 7 membered ring system connecting to R2 to R3,
wherein the 3 to 7 membered ring system connecting R2 to R3, when present, is an optionally substituted, fully saturated or unsaturated, aromatic or a nonaromatic cyclic or hetrocyclic group;
R4 is an alkyl or a carboxylic acid,
or a pharmaceutically acceptable salt thereof, a tautomer thereof, or a pharmaceutically acceptable salt of the tautomer.
2. A compound of claim 1 , wherein R1 is phenyl, R2 and R3 is a heterocycle which is a 4 membered ring system, and R4 is a carboxylic acid.