ethyl 5-oxopentanoate

Conditions: temp:0.00; pressure:0.00; stir:

Conditions: temp:0.00; pressure:0.00; stir:

Conditions: temp:10.01; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: Heptyltriphenylphosphonium bromide (16.8g), prepared from 1-bromoheptane and triphenylphosphine analogously to undecyltriphenylphosphonium bromide as described in Example 2(2), is suspended in dry ether (300 ml) and the mixture is treated whilst stirring under nitrogen with 1.7 M butyllithium in hexane (36 ml) from a syringe. The resulting bright red solution is cooled to 10° C. and treated dropwise with ethyl 5-oxopentanoate [5.5 g, prepared as described in Example 2 (1B)] in dry ether (37.5 ml). After 10 minutes, the reaction mixture is worked up by the procedure described in Example 2(2) to give ethyl (Z)-dodec-5-enoate as a yellow oil (8.6g). the mixture is treated

Conditions: temp:10.01; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: Undecyltriphenylphosphonium bromide (16.3 g, prepared by heating 1-bromoundecane and triphenylphosphine together in refluxing xylene) is suspended in dry ether (400 ml) and the mixture is stirred under nitrogen whilst 1.7 M butyllithium in hexane (47.5 ml) is added from a syringe. The resulting bright red solution is cooled to 10° C. and treated dropwise with ethyl 5-oxopentanoate (7.25 g) in dry ether (50 ml). After 10 minutes, water (200 ml) is added and when the solid product has dissolved the ether layer is separated and the aqueous layer is washed with ether (3×100 ml). The combined ethereal solutions are dried over magnesium sulphate and the ether is evaporated. The residue is shaken with hexane (200 ml), and the mixture is cooled and filtered. The filtrate is concentrated to a volume of 100 ml and then cooled to allow crystallisation of the triphenylphosphine oxide. When this is complete, the mixture is filtered and the filtrate is evaporated to yield ethyl (Z)-hexadec-5-enoate in crude form as a yellow oil (10.1 g). is added from a syringe is separated the aqueous layer is washed with ether (3×100 ml) The combined ethereal solutions are dried over magnesium sulphate the ether is evaporated the mixture is cooled filtered The filtrate is concentrated to a volume of 100 ml cooled crystallisation of the triphenylphosphine oxide When this is complete, the mixture is filtered the filtrate is evaporated

Conditions: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: Ethyl 5-bromopentanoate (42 g), sodium bicarbonate (34 g) and pyridine N-oxide (38 g) in toluene (250 ml) are heated together under reflux in an atmosphere of nitrogen with vigorous stirring for 9 hours. After cooling, the product is partitioned with water (400 ml). The toluene layer is separated and the aqueous layer is extracted with a further amount of toluene (100 ml). The combined toluene extracts are dried over magnesium sulphate and the toluene removed by fractional distillation. The residue is distilled under vacuum to give ethyl 5-oxopentanoate as a colourless oil (14.1 g), m.s. M+ 144. under reflux in an atmosphere of nitrogen After cooling the product is partitioned with water (400 ml) The toluene layer is separated the aqueous layer is extracted with a further amount of toluene (100 ml) The combined toluene extracts are dried over magnesium sulphate the toluene removed by fractional distillation The residue is distilled under vacuum

Conditions: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: With stirring, 14.4 g (100 mmol) of ethyl 5-oxopentanoate, 9.2 g (112.6 mmol) of dimethylammonium chloride and 10.8 ml (117 mmol) of 37% formaldehyde solution are heated to 100° C. The mixture is cooled and extracted with 3×30 ml of diethyl ether. The batch is cooled and the organic phases are combined, washed with a saturated solution of sodium chloride, dried over magnesium sulfate and evaporated to dryness, giving ethyl 4-formylpent-4-enoate as a colorless oil which can be further reacted without additional purification. The mixture is cooled extracted with 3×30 ml of diethyl ether The batch is cooled washed with a saturated solution of sodium chloride dried over magnesium sulfate evaporated to dryness

Conditions: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: With stirring, 14.4 g (100 mmol) of ethyl 5-oxopentanoate, 9.2 g (112.6 mmol) of dimethylammonium chloride and 10.8 ml (117 mmol) of 37% formaldehyde solution are heated to 100° C. The mixture is cooled and extracted with 3×30 ml of diethyl ether. The batch is cooled and the organic phases are combined, washed with a saturated solution of sodium chloride, dried over magnesium sulfate and evaporated to dryness, giving ethyl 4-formylpent-4-enoate as a colorless oil which can be further reacted without additional purification. The mixture is cooled extracted with 3×30 ml of diethyl ether The batch is cooled washed with a saturated solution of sodium chloride dried over magnesium sulfate evaporated to dryness

Conditions: temp:10.01; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: Heptyltriphenylphosphonium bromide (16.8g), prepared from 1-bromoheptane and triphenylphosphine analogously to undecyltriphenylphosphonium bromide as described in Example 2(2), is suspended in dry ether (300 ml) and the mixture is treated whilst stirring under nitrogen with 1.7 M butyllithium in hexane (36 ml) from a syringe. The resulting bright red solution is cooled to 10° C. and treated dropwise with ethyl 5-oxopentanoate [5.5 g, prepared as described in Example 2 (1B)] in dry ether (37.5 ml). After 10 minutes, the reaction mixture is worked up by the procedure described in Example 2(2) to give ethyl (Z)-dodec-5-enoate as a yellow oil (8.6g). the mixture is treated

Conditions: temp:10.01; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: Undecyltriphenylphosphonium bromide (16.3 g, prepared by heating 1-bromoundecane and triphenylphosphine together in refluxing xylene) is suspended in dry ether (400 ml) and the mixture is stirred under nitrogen whilst 1.7 M butyllithium in hexane (47.5 ml) is added from a syringe. The resulting bright red solution is cooled to 10° C. and treated dropwise with ethyl 5-oxopentanoate (7.25 g) in dry ether (50 ml). After 10 minutes, water (200 ml) is added and when the solid product has dissolved the ether layer is separated and the aqueous layer is washed with ether (3×100 ml). The combined ethereal solutions are dried over magnesium sulphate and the ether is evaporated. The residue is shaken with hexane (200 ml), and the mixture is cooled and filtered. The filtrate is concentrated to a volume of 100 ml and then cooled to allow crystallisation of the triphenylphosphine oxide. When this is complete, the mixture is filtered and the filtrate is evaporated to yield ethyl (Z)-hexadec-5-enoate in crude form as a yellow oil (10.1 g). is added from a syringe is separated the aqueous layer is washed with ether (3×100 ml) The combined ethereal solutions are dried over magnesium sulphate the ether is evaporated the mixture is cooled filtered The filtrate is concentrated to a volume of 100 ml cooled crystallisation of the triphenylphosphine oxide When this is complete, the mixture is filtered the filtrate is evaporated

Conditions: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: Ethyl 5-bromopentanoate (42 g), sodium bicarbonate (34 g) and pyridine N-oxide (38 g) in toluene (250 ml) are heated together under reflux in an atmosphere of nitrogen with vigorous stirring for 9 hours. After cooling, the product is partitioned with water (400 ml). The toluene layer is separated and the aqueous layer is extracted with a further amount of toluene (100 ml). The combined toluene extracts are dried over magnesium sulphate and the toluene removed by fractional distillation. The residue is distilled under vacuum to give ethyl 5-oxopentanoate as a colourless oil (14.1 g), m.s. M+ 144. under reflux in an atmosphere of nitrogen After cooling the product is partitioned with water (400 ml) The toluene layer is separated the aqueous layer is extracted with a further amount of toluene (100 ml) The combined toluene extracts are dried over magnesium sulphate the toluene removed by fractional distillation The residue is distilled under vacuum

Conditions: temp:0.00; pressure:0.00; stir:

Conditions: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: The process is performed as in Example 3 for the preparation of 10-(2-carboxybenzylidene)-5H,10H-imidazo[1,2-a]indeno[1,2-e]pyrazin-4-one but starting with 3.3 g of 5H,10H-imidazo[1,2-a]indeno[1,2-e]-pyrazin-4-one, 66 ml of dimethyl sulphoxide, 2.35 g of ethyl 5-oxopentanoate and 1.06 g of sodium hydride. After treatment of the reaction mixture with water (66 ml) and with acetic acid (6.6 ml), the suspension obtained is filtered, the insoluble product is washed with water (50 ml), with methanol (25 ml) and then with ethyl ether (2×25 ml) and dried at 60° C. under reduced pressure. The solid obtained is suspended in a mixture of 70 ml of ethanol and 6 ml of 1ON sodium hydroxide, filtered off, washed with ethanol and purified by dissolution in 15 ml of water and precipitation with 15 ml of IN hydrochloric acid. The precipitate is filtered off, washed with water (2×10 ml), triturated at the reflux of methanol (200 ml), filtered off and dried. 0.4 g of 5-(4-hydroxyimidazo[1,2-a]indeno-[1,2-e]pyrazin-10-ylidene]pentanoic acid is obtained, which product is converted into the disodium salt of formula C18H13N3O3Na2 (Analysis, % calculated C: 59.18, H: 3.59, N: 11.50, O: 13.14, Na: 12.59, % found C 58.8, H: 3.4, N: 11.5). is filtered the insoluble product is washed with water (50 ml), with methanol (25 ml) with ethyl ether (2×25 ml) and dried at 60° C. under reduced pressure The solid obtained filtered off washed with ethanol purified by dissolution in 15 ml of water precipitation with 15 ml of IN hydrochloric acid The precipitate is filtered off washed with water (2×10 ml) triturated at the reflux of methanol (200 ml) filtered off dried