Continuous-flow retro-Diels–Alder reaction: an efficient method for the preparation of pyrimidinone derivatives

• Imane Nekkaa,
• Márta Palkó,
• István M. Mándity and
• Ferenc Fülöp

Beilstein J. Org. Chem. 2018, 14, 318–324, doi:10.3762/bjoc.14.20

• confirm the viability of preparing the desired pyrimidinones in short reaction times. Yields typically higher than those published earlier using conventional batch or microwave processes were achieved. Keywords: continuous-flow; desulfurisation; norbornene-fused heterocycles; pyrimidinones; retro-Diels

• our system. Surprisingly, however, we could detect traces of di-endo-3-phenyl-4a,5,8,8a-tetrahydro-5,8-ethanoquinazolin-4(3H)-one (15b), resulting from desulfurisation of 8b (Scheme 2). This observation prompted us to investigate whether desulfurisation can occur under the flow reactor conditions. In

• the literature, a similar desulfurisation batch reaction was performed with nickel catalysis, in ethanol (EtOH)/water (2:1) solution [55][56][57]. Thus, thioxo derivative 8b was dissolved in this mixture, and the CF method was repeated. Desulfurisation of 8b, at 250 °C without adding any catalytic

Part 2. Mechanistic aspects of the reduction of S-alkyl- thionocarbonates in the presence of triethylborane and air

• Florent Allais,
• Jean Boivin and
• Van Tai Nguyen

Beilstein J. Org. Chem. 2007, 3, No. 46, doi:10.1186/1860-5397-3-46

• corresponding alkanes with good to excellent yields. Such a process complies with the long-standing pursuit of an environmentally acceptable process for desulfurisation, dehalogenation or deoxygenation that operates under mild reaction conditions. In this context, special attention must be paid to a paper

A convenient allylsilane- N-acyliminium route toward indolizidine and quinolizidine alkaloids

• Roland Remuson

Beilstein J. Org. Chem. 2007, 3, No. 32, doi:10.1186/1860-5397-3-32

• were the conversion of 7b into its dithiolane and subsequent desulfurisation using Raney nickel. The synthesis of (-)-indolizidine 167B 1 has been achieved in 7 steps with a 17% overall yield from ethyl (3R)-3-aminohexanoate 2 with an enantiomeric excess of 93%. [19] I 1.2 Intermolecular cyclisation