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14.4.4.1.1.1.1.1 Variation 1: Direct Conversion of 4H-1-Benzopyran-4-ones into 4H-1-Benzopyran-4-thiones

DOI: 10.1055/sos-SD-014-00294

Williams, A. C.; Camp, N.Science of Synthesis, (200314533.

This method has proved suitable for the preparation of simple 4H-1-benzopyran-4-thiones (e.g., 567, 568),[‌785‌,‌792‌,‌797‌] benzo- and furo-fused derivatives,[‌795‌,‌796‌] as well as a range of more highly substituted 2-aryl- and 3-aryl-4H-1-benzopyran-4-ones (e.g., 569, 570) (Scheme 183).[‌798‌‌800‌] The procedure involves heating the substrate and Lawesson's reagent together in a suitable solvent, typically dry toluene, but xylene and benzene have also been used. The products are isolated by chromatography and/or recrystallization from a suitable solvent after removal of the reaction solvent. Microwave heating of mixtures of solid substrates and Lawesson's reagent obviates the necessity for solvent and greatly reduces reaction times.[‌405‌]

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Meeeeeeeeeee Meeeeeeeee

8-(Meeeeeeeeeeee)-8-eeeeee-8M-8-eeeeeeeeee-8-eeeeee (888):[‌888‌]

M eeeeeee ee 8-(eeeeeeeeeeeee)-8-eeeeee-8M-8-eeeeeeeeee-8-eee (88.8e, 8.8888eee) eee Meeeeeee'e eeeeeee (88.8e, 8.8888eee) ee eeeeee (888eM) eee eeeeeee ee 88°M eee 88eee. Meeee eeeeeee ee ee, eee eeeeeeeeeee eee eeeeeeee eee eee eeeeeeee eeeeeeeeee ee eeeeeee. Mee eeeeeee eee eeeeeeee ee eeeeeeeeeeeeee (eeeeee eee, MMMe8) eeeeeeee ee eeeeeeeeeeeeeeeee (MeMM) ee eeee eee eeeeeeee; eeeee: 88.8e (88%); ee 888°M.

8-(8-Meeee)-8M-8-eeeeeeeeee-8-eeeeee (888, M8=8-Mee; M8=M); Meeeeee Meeeeeeee:[‌888‌]

M eeeeeee ee 8-(8-eeeee)-8M-8-eeeeeeeeee-8-eee (8.88e, 8eeee), Meeeeeee'e eeeeeee (8.88e, 8eeee), eee eee eeeeeee (88eM) eee eeeeee eeeee eeeeee eee 8e. Mee eeeeeee eee eeeeeee eeeee eeeeeee eeeeeeee eee eee eeeeeee eeeeeeeeeeeeee (MeMM) ee eeee eeeeee eeeeeeee; eeeee: 8.88e (88%); ee 888888°M.

8-Meeeeee-8-(8-eeeeeeeeeeeee)-8M-8-eeeeeeeeee-8-eeeeee (888, M8=MMe; M8=MMe); Meeeeee Meeeeeeee:[‌888‌]

Me eeeeeeee eeeeeee ee 8-eeeeeee-8-(8-eeeeeeeeeeeee)-8M-8-eeeeeeeeee-8-eee (888ee, 8eeee) eee Meeeeeee'e eeeeeee (888ee, 8.8eeee) eee eeeeee ee e eeeee eeee, eeeee eee eeee eeeeee ee ee eeeeeee eeee eeeeee e eeeeeeee eeeeeeeee eeee (888M) eee eeeeeeeeee eee 8eee: eee eeeeeeee ee eee eeeeeeee eee eeeeeeeee ee MMM eeeeeeeeeee. Meee eeeeeeeeee eee eeeeeee eee eeeeeeeee ee MM8Me8, eeeeeeee ee eeeeee eee, eee eeeeee eeeee eeee eeeeee, eeee MeMMe/eeeeee (8:8) ee eeeeee eee eeeeeee; eeeee: 888ee (88%).

8-(Meeeeeeeeeee)-8-eeeeeee-8M-8-eeeeeeeeee-8-eeeeee (888, M8=M8=M8=M; M8=MMe; M8=MMe8); Meeeeee Meeeeeeee:[‌888‌]

M eeeeeee ee 8-(eeeeeeeeeeee)-8-eeeeeee-8M-8-eeeeeeeeee-8-eee (8e, 8eeee) eee M8M8 (8e, 8eeee) ee eee eeeeeeee (88eM) eee eeeeee eeeee eeeeee eee 8e eeee eeeeee eeee eeeeeee eee. Mee eeeeeeeeeee eee eeeeeeeee, eeeeee eeee M8M eee eeeeeeeeeeeeee (MeMM) ee eeee e eeeeee eeeee; eeeee: 8.8e (88%); ee 888888°M.

Meeee [8-(8-Meeeee-8M-8-eeeeeeeeee-8-ee)eeeeee]eeeeeee (888, M8=M8=M8=M8=M; M8=Me); Meeeeee Meeeeeeee:[‌888‌]

Meeee [8-(8-eee-8M-8-eeeeeeeeee-8-ee)eeeeee]eeeeeee (8e, 8.8eeee) eee eeeeeeeee ee eeeeeeee (88eM) eee eeeeeee eeee M8M8 (8e, 8.8eeee). Mee eeeeeee eee eeeeee eeeee eeeeee eee 8e eeee eeeeee eee eeeeee eeee eeee M8M, eeeeeeee eeeeeeeeee. Mee eeeeee eeeeeeeeeee eee eeeeeeeee ee eeeeeeeeee eee eeeeeeeeeeeeee (MeMM); eeeee: 8.8e (88%); ee 8888°M.

References


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