From start-up to maximum loading: An approach for methane production in upflow anaerobic sludge blanket reactor fed with the liquid fraction of fruit and vegetable waste.

This investigation provides a reproducible approach for determining the limits of an upflow anaerobic sludge blanket (UASB) reactor designed for the methanization of the liquid fraction of fruit and vegetable waste (FVWL). Two identical mesophilic UASB reactors were operated for 240 days with a three-day fixed hydraulic retention time and an organic load rate (OLR) increased from 1.8 to 10 gCOD L-1 d-1. Because of the previous estimation of flocculent-inoculum methanogenic activity, it was possible to design a safe OLR for the quick start-up of both UASB reactors. The operational variables obtained from the operation of the UASB reactors did not show statistical differences, ensuring the experiment's reproducibility. As a result, the reactors achieved methane yield close to 0.250 LCH4 gCOD-1 up to the OLR of 7.7 gCOD L-1 d-1. Furthermore, the maximum volumetric methane production rate of 2.0 LCH4 L-1 d-1 was discovered for the OLR ranges between 7.7 and 10 gCOD L-1 d-1. The possible overload at OLR of 10 gCOD L-1 d-1 resulted in a significant reduction of methane production in both UASB reactors. Based on the methanogenic activity of the UASB reactors sludge, a maximum loading capacity of approximately 8 gCOD L-1 d-1 was estimated.

Long-acting contraceptive agents: norethisterone esters of monoalkenyl and monoalkynyl acids.

The synthesis of nine new esters of norethisterone (17 alpha-ethynyl-17 beta-hydroxyestr-4-en-3-one) is described, with the esterifying acids bearing an acetylenic or olefinic function in a chain of eight or nine carbon atoms, for evaluation as long-acting contraceptive agents.

Long-acting contraceptive agents: esters of norethisterone with alkoxy- and halogeno-substituted carboxylic acids.

The chemical synthesis and physical data of several new esters of norethisterone (17 alpha-ethynyl-17 beta-hydroxyestr-4-en-3-one) are reported, which contain either a chloro- or an alkoxy-group as a substituent in the acid side-chain.

Long-acting contraceptive agents: norethisterone esters of polyunsaturated acids.

Some new derivatives of norethisterone (17 alpha-ethynyl-17 beta-hydroxyestr-4-en-3-one) are described in which the 17 beta-hydroxyl group of the steroid is esterified with polyunsaturated aliphatic acids. The potential of these compounds as long-acting contraceptive agents has been evaluated.

Potential long-acting contraceptive agents: esters of testosterone with alkoxy- and halogeno-substituted carboxylic acids.

The chemical synthesis and physical data of several new esters of testosterone (17 beta-hydroxyandrost-4-en-3-one), which contain either a halogeno or an alkoxy substituent in the acid chain, are reported.

Long-acting contraceptive agents: testosterone esters of unsaturated acids.

The synthesis of 13 new esters of testosterone is described, with the esterifying acids bearing acetylenic, olefinic, or polyunsaturated functions in the chain, for evaluation as long-acting androgens.

PIP: A program of the World Health Organization for developing long-acting esters of testosterone that would exhibit a more constant release rate and maintain testosterone levels in the normal range longer than testosterone enanthate found that these esters had a role in fertility, and gerontology. The synthesis of 13 new esters of testosterone is described, with the esterifying acids bearing acetylenic, olefinic or polyunsaturated functions in the chain, for evaluation as long-acting androgens. The nuclear magnetic resonance (NMR) images were recorded on a spectrometer. The samples were recorded in tubes using CDC13 as solvent. The NMR spectra were recorded with Perkin-Elmer instrument in CDC13, with tetramethylsilane as internal reference. Infrared spectra were measured on the same spectrometer. Mass spectra were also recorded. Thin-layer chromatography was performed on Merck silica gel and the spray reagent was iodine or vanillin. To a solution of testosterone the corresponding acid chloride was added yielding the pure ester after the usual work-up. E-5-methylhexa-2,4-dienoic (IXb), 5- phenylpenta-2-,4-dienoic (Xb), 5-phenyl-4-yn-pent-2-enoic (XIb), and non-4-en-6-ynoic acid (XIIb), were required for the synthesis. Esterification of testosterone with each of the first 12 unsaturated acids was performed by reaction with the corresponding acid chlorides in pyridine. Although the nona-2,3-dienoic acid ethyl ester was easily obtained, this compound could not be hydrolyzed to the acid (XIIIb). Hence, an alternative procedure was tried for the synthesis of the ester XIIIa, by reaction of bromoacetate of testosterone (XIVa) with triphenylphosphine to give the phosphorane (XVa). Reaction of this phosphorane (XVa) with 1-diazoheptan-2-one (XVI) led to the allenic ester (XIIIa).

Long-acting contraceptive agents: norethisterone esters of arylcarboxylic acids.

The synthesis of esters of norethisterone (17 alpha-ethynyl-17 beta-hydroxy-estr-4-en-3-one) with acids containing a benzene ring is described, two methods of esterification being compared in terms of yield and convenience. The activities of these esters as long-acting contraceptive agents have been evaluated.

Long-acting contraceptive agents: levonorgestrel esters of unsaturated acids.

Esters of levonorgestrel (13 beta-ethyl-17 beta-ethynyl-17 beta-hydroxygon-4-en-3-one) with a variety of unsaturated carboxylic acids have been synthesized for evaluation as potential long-acting, injectable contraceptive agents.

PIP: This paper describes the synthesis of esters of levonorgestrel (13 beta-ethyl-17 beta-ethynyl-17 beta-hydroxygon-4-en-3-one) with a variety of unsaturated carboxylic acids for evaluation as potential longacting injectable contraceptive agents. 1-Cyclohexenylacetic acid was prepared by the hydrolysis of 1-cyclohexenylacetonitrile. The synthesis of E-penta-2,4-dienoic acid was achieved by the condensation of acrolein with malonic acid. Reformatsky reaction between crotonaldehyde and ethyl 2-bromopropionate followed by dehydration of the condensation product was used for the synthesis of E,E-2-methylhexa-2,4-dienoic acid. In the preparation of 5-methyl-2-furylacetic acid, 5-methylfurfural was subjected to condensation reaction with rhodanine followed by hydrolysis. The levonorgestrel esters were synthesized by reaction of the appropriate acid chloride with the thallim salt of levonorgestrel, which was obtained by use of thallous ethoxide. The esters prepared were levonorgestrel 1-cyclohexenylacetate; levonorgestrel 1-cyclopentenylacetate; levonorgestrel E-penta-2,4-dienoate; levonorgestrel E,E-2methylhexa-2,4-dienoate; levonorgestrel 5-methyl-2-furylethaoate; levonorgestrel 3-(5'-methyl-2'-furyl)propanoate; levonorgestrel 3-(5'-ethyl-2'-furyl)propanoate; leveonorgestrel 4-(5'-methyl-2'-furyl)butanoate; levonorgestrel E-non-2-en-4-ynoate; 1-cyclohexenylacetic acid; 1-cyclopentenylacetic acid; E-penta-2,4-dienoic acid; E,E-2-methylhexa-2,4-dienoic acid; 5-methyl-2-furylacetic acid; and E-non-2-en-4-ynoic acid.

Reductive fragmentation of carbohydrate anomeric alkoxy radicals. Synthesis of alditols with potential utility as chiral synthons.

A series of anomeric nitrate esters and N-phthalimido glycosides of carbohydrates in furanose and pyranose forms have been synthesized in order to generate the corresponding alkoxy radicals and study the C1-C2 fragmentation reaction under reductive conditions. This reaction constitutes a two-step method for the transformation of carbohydrates into the corresponding alditols with one less carbon. Using this methodology, interesting four- and five-carbon building blocks for natural products synthesis possessing D-erythritol, D-threitol, D-xylitol, and D-arabinitol stereochemistry have been prepared. The synthesis of 1,2-O-isopropylidene-beta-L-threose (40) and 1-acetamido-2,4,5-tri-O-acetyl-D-arabinitol (50) have also been achieved from 1,2:5,6-di-O-isopropylidene-beta-D-glucofuranose and 2-acetamido-3,4,6-tri-O-acetyl-2-deoxy-D-glucopyranose, respectively.

Fragmentation of carbohydrate anomeric alkoxy radicals. synthesis of polyhydroxy piperidines and pyrrolidines related to carbohydrates.

Imino sugars of the piperidine and pyrrolidine types can be specifically obtained when protected 5-amino-5-deoxyfuranopentoses, 5-amino-5-deoxyfuranohexoses, 6-amino-6-deoxyfuranohexoses, and 6-amino-6-deoxypyranohexoses undergo a tandem alkoxy radical beta-fragmentation-intramolecular cyclization reaction. The reaction is promoted by the system: iodosylbenzene-iodine under mild conditions. The tert-butoxycarbonyl, benzyloxycarbonyl, and diphenylphosphinoyl radicals have been studied as amino-protecting groups. Using this methodology, polyhydroxylated pyrrolidines of the D-erythrofuranoses 34 and 35, D-threofuranose 36, L-xylofuranose 42, and D-arabinofuranose 43 series and polyhydroxylated piperidines of the D-arabinopyranose type 37 and 38 were obtained.