618118-89-1Relevant academic research and scientific papers
A study of the ring-opening of lactides and related cyclic esters by Ph2SnX2 and Ph3SnX compounds (X = NMe 2, OR)
Chisholm, Malcolm H.,Delbridge, Ewan E.
, p. 1167 - 1176 (2003)
Ph3SnX reacts with L-lactide in the order X = NMe 2～OMe ? OPri > OBut in the initial ring-opening event. The rate of ring-opening of methyl substituted 1,4-dioxane-2,5-diones decreases with methyl substitution and ring-opening of 3,3,6,6-tetramethyl-1,4-dioxane-2,5-dione is not observed. From studies of the reaction between Ph3SnOPri and L-lactide the activation parameters ΔH≠ = 13(1) kcal mol-1 and ΔS≠ = -37(3) eu have been determined. Ph 3SnNMe2 reacts with cyclic esters and propylene carbonate at low temperatures to give isolable ring-opened products. The compound Ph 3Sn[OCHMeC(O)OCHMeC(O)X] (where X = NMe2, OMe) are labile in solution at room temperature, yielding Ph3Sn[OCHMeC(O)X] and Ph3Sn[OCHMeC(O)]nX, where n ≥ 3, by transesterification, along with other minor products due to phenyl/OR group transfer (i.e., Ph4Sn). Ph2Sn(NMe2) 2 and L-lactide react to give Ph2Sn[OCHMeC(O)NMe 2]2 by ring-opening of L-lactide followed by rapid amidation. A related compound, Ph2Sn[OCHMeC(O)OPri] 2, is also formed in the reaction between Ph2Sn(OPr i)2 and L-lactide but is more labile toward further ring-opening of L-lactide.
Ring-opening of lactides and related cyclic monomers by triaryltin(IV) alkoxides and amides
Chisholm,Delbridge
, p. 1308 - 1309 (2007/10/03)
Ar3SnX, where Ar = p-MeC6H4, p-CF3C6H4 or Ph and X = OBut or NMe2, are catalyst precursors for the ring-opening of lactides in benzene at 80°C and the rate of ring-ope
