Vitamin K, synthesis

Additionally, with chronic hypoxia, normal hemoglobin and hematocrit values may represent relative anemia.12 Increased red blood cell production is a physiologic response to hypoxia however, this response may be blunted in CF and may result in symptoms of anemia despite normal lab values. Abnormal bleeding may also be observed as a result of vitamin K malabsorption or antibiotic-associated depletion of gastrointestinal flora and vitamin K synthesis. 

Compounds of type LXXIII cannot be made by the rearrangement of the 7-substituted allyl ethers, because these compounds yield LXXIV by inversion. a,7-Dimethylallyl bromide,16 7,7-dimethylallyl bromide,29 cinnamyl chloride,84 and phytyl bromide 86 (a vitamin K synthesis) have been used in C-alkylation procedures. The silver salt of 2-hydroxy-l,4-naphthoquinone is converted to a mixture of C-alkylation product and two isomeric ethers by treatment with allylic halides and benzyl halides. ... 

Altered gut vitamin K synthesis. Vitamin K antagonizes the effects of warfarin. External sources of vitamin K include the diet and intestinal flora, the latter only becoming significant in those with a low dietary intake of the vitamin. Broad-spectrum antibiotics that may reduce intestinal bacteria may alter the effect of warfarin. 

Aspirin potentiates the anticoagulant effect of warfarin and other coumarins because of its inhibitory effect on platelet aggregation and inhibition of vitamin K synthesis. Ibuprofen may also enhance the effect of anticoagulants. Patients on anticoagulant therapy should avoid over-the-counter (OTC) aspirin and ibuprofen. 

Sometimes reaction rates can be enhanced by using multifunctional reactors, i.e., reactors in which more than one function (or operation) can be performed. Examples of reactors with such multifunctional capability, or combo reactors, are distillation column reactors in which one of the products of a reversible reaction is continuously removed by distillation thus driving the reaction forward extractive reaction biphasing membrane reactors in which separation is accomplished by using a reactor with membrane walls and simulated moving-bed (SMB) reactors in which reaction is combined with adsorption. Typical industrial applications of multifunctional reactors are esterification of acetic acid to methyl acetate in a distillation column reactor, synthesis of methyl-fer-butyl ether (MTBE) in a similar reactor, vitamin K synthesis in a membrane reactor, oxidative coupling of methane to produce ethane and ethylene in a similar reactor, and esterification of acetic acid to ethyl acetate in an SMB reactor. These specialized reactors are increasingly used in industry, mainly because of the obvious reduction in the number of equipment. These reactors are considered by Eair in Chapter 12. 

Inhibitory effect on intestinal vitamin K synthesis, VI, 41 7,12-DiketochoIanic acid, configuration, VIII, 261 Dimenformon, see Estradiol benzoate 2,3-Dimercaptopropanol (BAL), as antidote against lewisite, VII, 106 mercury, VII, 106 mustard gas, VII, 106... 

The biosynthesis of compounds derived from shikimic acid is closely linked to that of isomers of vitamin K (35) (Fig. 6.7). In plants and in microorganisms, die aromatic ring is formed via the shikimate pathway, which does not exist in animals. Only recently has it been established that vitamin K synthesis branches from wo-chorismic acid (36) and not from chorismic acid (37). fro-Chorismic acid (36) is derived from shikimic acid (see Chapter 7) (Leistner, 1986). Both of the cyclization steps leading to naphthoquinones and vitamin K are unusual in plants. 

C. Some products include 9ullaquinoxaUne> which enharxies toxicity by inhibiting vitamin K synthesis in the intestine and colon. 

Kaipling, S., Soli, J., and Schultz, G., Site of methylation of 2-phytyl-l,4-naphthoquinol in phyl-loquinone (vitamin K,) synthesis in spinach chloroplasts. Phytochemistry, 23, 89, 1984. 

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