A convenient preparation of methyl 2,5-dihydro-2-oxo-3-furancarboxylate

Convergent syntheses of 9-deoxy-12-phenylthioprostanoids and 9-deoxy-Δ8(12)-PGD1derivatives

“…, its 12a-Phenylthio Zsomer (17), and their Methyl Esters (13) and (18).+a) A solution of pyridinium dichromate '7 (19.0 g, 28.7 mmol) in DMF (20 ml) was added to a stirred solution of the alcohol (11) (2.0 g, 4.65 mmol) in DMF (5 ml). After 24 h at room temperature, dilution with water and the usual work-up with ether gave an oil which was chromatographed [ethyl acetate-light petroleum (1:1)] to afford the acid (12) (1.6 g, 78%), v,,,. 3 500 and 3 030 (CO,H), 1 720 (O), 1 700 (CO,H), and 1690 and 1610 cm-' (C--CC==O); m,Hz,m,2 x COCH, and CH,CO,H), 1.95-1.00 (19 H, m), and 0.87 (3 H,t,J 7 Hz,CH,CH,); m/z 444 ( M + ) (Found: C,70.1;H,8.2;S,7. (b) MCPBA (99 mg, 0.6 mmol) was added to a solution of 12aphenylthio-l-norprost-13-ene-l1,15-dione (14) (200 mg, 0.5 mmol) in dichloromethane (4 ml) at 0 "C. After 30 min, the mixture was allowed to warm to room temperature, and stirred for a further hour before being worked up with dichloromethane in the usual way.…”

Conjugate additions to α,β-unsaturated sulphoxides: syntheses of cyclopentenones and 9-deoxyprostanoids

“…(CHCl,) r-1 -Hexyl-t-2-hydroxymethyl-c-3-and -t-34 tetrahydropyran-2-yloxy)cyclopentane, (28) and (37).-A solution of the ester (27) (2.2 g, 67 mmol) in ether (5 ml) was added slowly to a cooled, stirred suspension of lithium aluminium hydride (0.5 g, 0.013 mol) in ether (35 ml). After the mixture had been stirred for 30 min at room temperature the usual work-up with ether gave r-1 -hexyl-t-2hydroxymethyl-c-3-( tetrahydropyran-2-y1oxy)cyclopentane (28) (1.92 g, 99%) as an oil, v,,,~(CHCl,) 3 620 and 3450cm-'(OH);64.75and4.58(1 H,m,OCHO),4.17 ( Hydroxymethy l-r-1 -( tetrahydropyran-2-yloxy)-c-3-and tc-2-Hydroxymethyl-r-1 -( tetrahydropyran-2-yloxy)-t-3-[7-(tetrahydropyran-2-yloxy)heptyl]cyclopentane (32) and (41).-Reduction of the ester (31) (130 mg) with lithium aluminium hydride in the above manner gave the t-2-hydroxymethyl-r-ltetrahydropyranyloxy isomer (32) t-2-Formyl-r-1-hexyl-c-3andt-3-( tetrahydropyran-2-y1oxy)cyclopentane, (29) and (38), and Their Analogues (33) and (42)-A solution of the hydroxymethyl compound (28) (1.7 g, 6 mmol) in dichloromethane (50 ml) was added to a solution of dipyridine chromium trioxide 3 7 (9.73 g, 36 mmol) in dichloromethane (150 ml) at 20 "C. After 30 min the organic phase was decanted off and the residue was washed with dichloromethane. The combined dichloromethane extracts were washed with water, dried (MgSO,), and evaporated, to furnish the aldehyde (29) (1.69 g, 9973, v,,,.…”

“…After the mixture had been stirred for 30 min at room temperature the usual work-up with ether gave r-1 -hexyl-t-2hydroxymethyl-c-3-( tetrahydropyran-2-y1oxy)cyclopentane (28) (1.92 g, 99%) as an oil, v,,,~(CHCl,) 3 620 and 3450cm-'(OH);64.75and4.58(1 H,m,OCHO),4.17 ( Hydroxymethy l-r-1 -( tetrahydropyran-2-yloxy)-c-3-and tc-2-Hydroxymethyl-r-1 -( tetrahydropyran-2-yloxy)-t-3-[7-(tetrahydropyran-2-yloxy)heptyl]cyclopentane (32) and (41).-Reduction of the ester (31) (130 mg) with lithium aluminium hydride in the above manner gave the t-2-hydroxymethyl-r-ltetrahydropyranyloxy isomer (32) t-2-Formyl-r-1-hexyl-c-3andt-3-( tetrahydropyran-2-y1oxy)cyclopentane, (29) and (38), and Their Analogues (33) and (42)-A solution of the hydroxymethyl compound (28) (1.7 g, 6 mmol) in dichloromethane (50 ml) was added to a solution of dipyridine chromium trioxide 3 7 (9.73 g, 36 mmol) in dichloromethane (150 ml) at 20 "C. After 30 min the organic phase was decanted off and the residue was washed with dichloromethane. The combined dichloromethane extracts were washed with water, dried (MgSO,), and evaporated, to furnish the aldehyde (29) (1.69 g, 9973, v,,,. (CHCl,) 1 720 cm ' (CHO); 6 9 Oxidation of the isomeric hydroxymethyl compound (37) in the same way gave the aldehyde (38) (70%), v,,,,(CHCI,) 1 720 cm ' (CHO); 6 9.80 and 9.67 (1 H, both d, J 2 Hz, CHCHO in diastereoisomers owing to presence of THP ether), 4.60 (1 H, m, OCHO), 4.47 (1 H, q, J 8 Hz, CHOTHP), and 2.45 (1 H, m, CHCHO); m/z 282 ( M + ) (Found: C, 72.5; H, 10.6%).…”