Synthesen in der Carotinoid‐Reihe. 1. Mitteilung. Die technische Synthese von β‐Carotin

Abstract

The industrial β‐carotene manufacturing procedure based on Inhoffen's synthesis C19 + C2 + C19 = C40 is described. β‐Ionone is first lengthened to β‐C14‐aldehyde as in our vitamin A‐synthesis. By acetalisation, condensation with vinyl ether and treatment with acid the new β‐C16‐aldehyde is obtained. Repetition of the same reactions with propenyl ether leads to the β‐C19‐aldehyde. For the final steps simple methods were developed giving high yields. All the chemical, physical and biological constants of synthetic β‐carotene are identical with those of the natural compound. Exact data on light absorption are given. Extensive experiments with the synthetic β‐carotene on rats and rabbits show that even very large doses have no toxic effects.

The Action of Substituted 2-Furanacrolein Phenylhydrazones on Pathogenic Fungi

“…This was specially evident in the synthesis o f the 5-methyl 2-furanacrolein (yield 23.7%). The yield o f the product was increased considerably (48.3%) by the application o f the Isler and Hoaglin technique (16,17), using 5-methylfurfural and methyl vinyl ether in the presence o f trifluoride etherate. The 5-methyl 2-furanacrolein was synthesized for the first time by this method.…”

“…The resulting product was purified twice by fractional distillation at reduced pressure. The product separated at the temperature range b n i i o -1 1 2 0 C. with the yield o f 23 Due to the low yield, it was attempted to synthesize 5-methyl furanacrolein by the catalytic condensation o f 5-methyl furfural with methyl vinyl ether in the presence of boron trifluoridc etherate (16,17). The 48.3% yield o f the 5-methyl-2-furanacrolein obtained by this method was an improvement over the aldol condensation.…”

reKinetics and Mass Transfer in the Hydrogenation of 2-((1-benzyl-1,2,3,6-tetrahydropyridin-4-yl)methylene)-5,6-dimethoxy- -2,3-dihydroinden-1-one hydrochloride over Pt/C Catalyst

“…This important area of catalytic chemistry has been the foundation for the development of numerous diverse, small-and large-scale commercial hydrogenation processes, which include synthesis of fine and specialty chemicals such as agrochemicals 1,2 , flavours and fragrances [3][4][5][6][7][8] , food additives [9][10][11][12][13][14][15][16] and pharmaceuticals [17][18][19][20][21] . The hydrogenation of 2-((1-benzyl-1,2,3,6-tetrahydropyridin-4-yl)methylene)-5,6-dimethoxy-2,3--dihydroinden-1-one hydrochloride (1) to 2-((1-benzylpiperidin-4-yl)methyl)-5,6-dimethoxy-2,3-dihydroinden-1-one hydrochloride (4), which is the last production step for the preparation of (4), is one such industrial important reaction.…”

Allylic Sulfones Containing Triene Moieties as Key Synthons for Carotenoid Synthesis

“…These values are typical for strain-free acyclic sulfones. Two vicinal coupling constants with diastereotopic sp 3 -hybridized H-atoms at C(4) are 11.5 and 3.0 Hz, which indicate dihedral angles of ca. 1808 and ca.…”

“…Among the numerous approaches that have appeared in the literature to build the conjugated polyene chains of carotenoids [2], methods based on acetylide coupling/ partial hydrogenation [3] and Wittig olefination [4] have been the two main synthetic approaches. The Julia sulfone olefination protocol [5], which has been applied to retinol synthesis [6], is presumed to be the best method to produce double bonds with the (E)-configuration [7].…”