Synthesis of pyrimido[1,6-a]quinoxalines via intermolecular trapping of thermally generated acyl(quinoxalin-2-yl)ketenes by Schiff bases

Acyl(quinoxalin-2-yl)ketenes generated by thermal decarbonylation of 3-acylpyrrolo[1,2-a]quinoxaline-1,2,4(5H)-triones react regioselectively with Schiff bases under solvent-free conditions to form pyrimido[1,6-a]quinoxaline derivatives in good yields

Potassium Trifluorotris(pentafluoroethyl)phosphate

A transparent white crystalline product, K[(C2F5)3PF3] (KFAP), has been synthesized via a one-pot route. Difluorotris(pentafluoroethyl)phosphorane was reacted first with aqueous HF then with K2CO3 or KHCO3 in a solution. Isolation of the intermediate, tris(pentafluoroethyl)trifluorophosphoric acid H[(C2F5)3PF3] (HFAP), was not carried out. The salt has been characterised by powder and single crystal X-ray diffraction. The single-crystal structure shows a monoperiodic coordination polymer involving K∙∙∙F bridging interactions to be present. The thermal characteristics and behaviour of KFAP have been established by simultaneous TGA-DSC measurements