Synthesis of Diphytanyl Ether Analogues of Phosphatidic Acid and Cytidine Diphosphate Diglyceride

1971 ◽  
Vol 49 (3) ◽  
pp. 275-281 ◽  
Author(s):  
M. Kates ◽  
C. E. Park ◽  
B. Palameta ◽  
C. N. Joo
Keyword(s):  
Chemical Synthesis ◽  
Phosphatidic Acid ◽  
Physical Properties ◽  
Acid Hydrolysis ◽  
Anhydrous Benzene ◽  
Catalytic Hydrogenolysis ◽  
Cytidine Monophosphate ◽  
Cytidine Diphosphate

The chemical synthesis of 2,3-di-O-phytanyl-sn-1-glycerophosphate was carried out in two ways: (a) by phosphorylation of 2,3-diphytanyl-sn-glycerol with diphenylphosphoryl chloride in pyridine, followed by catalytic hydrogenolysis of the phenyl groups; and (b) by condensation of 1-iodo-2,3-di-O-phytanyl-sn-glycerol with silver di-p-nitrobenzyl phosphate in anhydrous benzene, followed by catalytic hydrogenolysis of the p-nitrobenzyl groups. The free diether phosphatidic acid obtained was converted to the dipotassium and disodium salts. The diether phosphatidic acid was also converted to the diether analogue of cytidine diphosphate diglyceride by condensation with cytidine monophosphate morpholidate in pyridine. The physical properties of these diether analogues are described, as well as their stabilities towards acid hydrolysis.

Chemical synthesis of poly(β-hydroxybutyrate) by the polymerization of (R,S)-β-butyrolactone with aluminoxane catalysts

1995 ◽  
Vol 41 (13) ◽  
pp. 274-281 ◽  
Author(s):  
Robert W. Lenz ◽  
John Yang ◽  
Bin Wu ◽  
C. Jeff Harlan ◽  
Andrew R. Barron
Keyword(s):  
Molecular Weight ◽  
Chemical Synthesis ◽  
Physical Properties ◽  
High Molecular Weight ◽  
Crystalline Polymers ◽  
Group 4 ◽  
Catalyst Systems

Racemic β-butyrolactone can be polymerized to crystalline polymers of reasonably high molecular weight by the use of aluminoxane catalysts. Investigations in this and other laboratories have shown that these polymers can be fairly highly isotactic, and in that form they are closely related in structure and physical properties to a reserve polyester produced by many bacteria: poly(β-hydroxybutyrate). In the present investigation, Ziegler–Natta type aluminoxane catalyst systems and a new aluminoxane derivative, tert-butylaluminoxane, were evaluated in attempts to polymerize racemic β-butyrolactone in higher yields to polymers of higher molecular weight and higher stereoregularity. The addition of group 4 metallocenes as cocatalysts for both methylaluminoxane and iso-butylaluminoxane catalysts gave higher yields of the isotactic polymer than those obtained with these catalysts alone, but surprisingly, the tert-butylaluminoxane catalysts produced predominantly syndiotactic rather than isotactic polymers.Key words: poly(β-hydroxybutyrate), β-butyrolactone, aluminoxane catalysts, isotactic poly(β-hydroxybutyrate), syndiotactic poly(β-hydroxybutyrate).

On the synthesis of 3,4-dihydroxyprolines. II. Synthesis, stereochemistry and reactivity of some 3,4-Epoxy-DL-proline derivatives

1975 ◽  
Vol 28 (11) ◽  
pp. 2479 ◽  
Author(s):  
CB Hudson ◽  
AV Robertson ◽  
WRJ Simpson
Keyword(s):  
Acid Hydrolysis ◽  
Methyl Esters ◽  
High Yield ◽  
Butyl Esters ◽  
Epoxy Acids ◽  
Trifluoroperacetic Acid ◽  
Catalytic Hydrogenolysis ◽  
Direct Separation ◽  
Proline Derivatives ◽  
Hydrolysis Of

N-Protected esters of 3,4-dehydro-DL-proline react with trifluoroperacetic acid to give, in high yield, approximately equal amounts of the corresponding stereoisomeric 3,4-epoxy-DL-proline derivatives, direct separation of which proved difficult. However individual members of the two families were obtained by discovery of selective transformations and fractionations. Relative configurations of the two 3,4-epoxy-N-tosylproline methyl esters were established by borohydride reduction to authentic 4-hydroxy-N-tosylprolinols. Epoxide reduction is regioselective. Extensive p.m.r. analyses then permitted stereochemical assignment of other derivatives. These epoxides are remarkably resistant to catalytic hydrogenolysis, and to hydration in acid or alkali. N-Substituted 3,4-epoxyproline methyl esters undergo ready β-elimination in alkali to yield the corresponding 4-hydroxy-2,3- dehydroproline esters and ultimately the N-substituted pyrrole-2- carboxylic acid or ester. Prolonged aqueous acid hydrolysis of 3,4- epoxy-N-tosylprolines, or of their methyl esters, gives mixtures of 3,4-dihydroxy-N-tosyl-DL-prolines in the 2,3-cis-3,4-trans and 2,3- trans-3,4-trans families. Their stereochemistry was allotted from p.m.r. of the diacetate methyl esters. During acid hydrolysis of 3,4- epoxy-N-tosylproline methyl esters, the ester of the trans stereoisomer hydrolyses selectively, and some epimerization of the cis stereoisomer occurs. Ester hydrolysis is much faster than epoxide hydration. Anhydrous acid cleavage of 3,4-epoxy-N-tosyl-DL-proline t-butyl esters to the epoxy acids is unusually slow.

Physical Properties of Resistant Mungbean Starch Prepared by Enzyme and Acid Treatment

2012 ◽  
Vol 554-556 ◽  
pp. 1033-1037 ◽  
Author(s):  
Qing Jie Sun ◽  
Liu Xiong ◽  
Ben Xin Xing ◽  
Cui Xia Sun
Keyword(s):  
Thermal Properties ◽  
Physical Properties ◽  
Acid Hydrolysis ◽  
Resistant Starch ◽  
Acid Treatment ◽  
Crystal Form ◽  
Peak Temperature ◽  
Water Binding

The physical properties of enzyme and acid treated mungbean RS were studied. The crystal form was transformed into B type from C type with enzymatic and acid treatment.The solubility and transmittance decreased and mungbean RS content and the water-binding values increased with increase in enzyme and acid hydrolysis. The thermal properties observed by DSC showed a decrease in enthalpy of gelatinization (ΔH) and increases in onset (To), peak temperature (Tp) and conclusion temperature (Tc) upon enzyme and acid hydrolysis. The ratio of volume of resistant starch samples wasn’t much different. However, a significant reduction in starch pasting viscosity was observed with enzyme and acid treating

scholarly journals Cellulose Nanofibers Preparation from Cassava Peels via Mechanical Disruption

Fibers ◽  
2019 ◽  
Vol 7 (5) ◽  
pp. 44
Author(s):  
Sonny Widiarto ◽  
Edi Pramono ◽  
Suharso ◽  
Achmad Rochliadi ◽  
I Made Arcana
Keyword(s):  
Physical Properties ◽  
Acid Hydrolysis ◽  
Alkali Treatment ◽  
Cellulose Nanofibers ◽  
Chemical Properties ◽  
Bleaching Process ◽  
Mechanical Disruption ◽  
Similar Chemical ◽  
Cassava Peels

In this study, cellulose and cellulose nanofibers (CNF) were extracted and prepared from cassava peels (CPs). The method of the cellulose extraction was performed by alkali treatment followed by a bleaching process. The CNF were prepared by mechanical disruption procedure (homogenization and ultrasonication), and the results were compared with a common acid hydrolysis procedure. The resulting cellulose and CNF from both procedures were then analyzed using FTIR, SEM, TEM, XRD, and TGA. The results show that cellulose and CNF were successfully prepared from both procedures. The physical properties of the produced CNF were different; however, they had similar chemical properties.

scholarly journals Biosynthesis of lecithin in brain. Participation of cytidine diphosphate choline and phosphatidic acid

1963 ◽  
Vol 87 (1) ◽  
pp. 128-136 ◽  
Author(s):  
KP STRICKLAND ◽  
D SUBRAHMANYAM ◽  
ET PRITCHARD ◽  
W THOMPSON ◽  
RJ ROSSITER
Keyword(s):  
Phosphatidic Acid ◽  
Cytidine Diphosphate

Evidence for Biosynthetical Equivalence of the Epimeric Isoleucine Residues in Angolide

1972 ◽  
Vol 50 (4) ◽  
pp. 428-439 ◽  
Author(s):  
R. O. Okotore ◽  
D. W. Russell
Keyword(s):  
Amino Acid ◽  
Physical Properties ◽  
Acid Hydrolysis ◽  
Column Chromatography ◽  
Mass Spectra ◽  
Mathematical Treatment ◽  
Amino Acid Residues ◽  
Analytical Results ◽  
Cyclic Intermediate

Pithomyces sacchari was grown on media containing L-valine. Instead of the metabolite angolide (cyclo-L-α-hydroxyisovaleryl1-erythro-L-isoleucyl2-L-α-hydroxyisovaleryl3-threo-D-isoleucyl4), synthesized on un-supplemented media, it produced a mixture with very similar physical properties. Acid hydrolysis liberated erythro-L- and threo-D-isoleucines (1:1), and DL-valine in amounts proportional to the exogenous valine concentration; L-α-hydroxyisovaleric acid was the only other component. Radioactivity from L-valine-U-14C was incorporated without dilution into valine, and with extensive dilution into the hydroxy acid.Partial fractionation of the mixture was achieved by column chromatography. Mass spectra of two fractions, containing different proportions of valine, were compared with the spectrum of angolide. A simple mathematical treatment showed that the fractions contained angolide, its divaline homologue, and a homologue with only one isoleucine replaced by valine. This must be a 1: 1 mixture of the two possible isomers, since any deviation from this ratio is inconsistent with the analytical results. It follows that the erythro-L- and the threo-D-isoleucine residues of angolide are equivalent with respect to their replacement by valine. It is inferred that angolide biosynthesis involves a cyclic intermediate containing both amino acid residues in the L configuration.

SYNTHESIS OF L-α-PHOSPHATIDYL-(α-METHYL)CHOLINES

1967 ◽  
Vol 45 (2) ◽  
pp. 309-316 ◽  
Author(s):  
Erich Baer ◽  
Bimal C. Pal
Keyword(s):  
Phosphatidic Acid ◽  
Phenyl Group ◽  
Iodide Ion ◽  
Catalytic Hydrogenolysis

The synthesis of a new group of phospholipids, L-α-phosphatidyl-DL-(α-methyl)cholines is reported. Three homologous members of this group were prepared by phosphorylating D-α,β-dimyristin, D-α,β-dipalmitin and D-α,β-distearin, respectively, with phenylphosphoryl dichloride and pyridine, esterifying the resulting phenyl esters of the L-α-phosphatidic acid monochlorides with DL-(α-methyl)choline iodide, replacing the iodide ion of the L-α-phosphatidyl-DL-(α-methyl)choline phenyl esters by acetate ion, and removing the phenyl group by catalytic hydrogenolysis.

scholarly journals Karakteristik Sifat Fisiko-Kimia dan Fungsional Pati Sagu Ihur (Metroxylon sylvestre) Dimodifikasi dengan Hidrolisis Asam

2018 ◽  
Vol 38 (1) ◽  
pp. 7
Author(s):  
Febby Jeanry Polnaya ◽  
Alfredo Andelson Huwae ◽  
Gilian Tetelepta
Keyword(s):  
Physical Properties ◽  
Acid Hydrolysis ◽  
Amylose Content ◽  
Chemical Properties ◽  
Heat Stability ◽  
Ash Content ◽  
Sago Starch ◽  
Native Starch ◽  
Swelling Power ◽  
Four Levels

The objective of this study was to characterize modified Ihur sago starch as affected by treatment of acid hydrolysis. A completely randomized experimental non-factorial design was used in this research with four levels of treatments, i.e. native ihur sago starch, HCl concentrations of 1.1 N, 2.2 N, or 3.3 N, subsequently. Physical properties such as color, swelling power, solubility, and paste clarity were measured in this research. Moisture, ash, and amylose content were determined as chemical properties, while the resistant starch (RS) content was determined for its functional properties. Results showed that starch treated with acid hydrolysis caused changes to physical properties in comparison with native starch. These included higher (80.93–81.89) degree of whiteness (L*) than native starch (80.29), lower redness (a*) and yellowness (b*) than native (8.26 and 18.24) having the value of 5.13–6.34, and 13.21–15.39, respectively. Acid hydrolysis not only caused a decrease in swelling power (43.88–50.56%), but also an increase in solubility (8.92–12.34%) and paste clarity (74.70–77.73% T) compared to native starch. Higher moisture and ash content having the value of 8.72–15.01% and 0.22–0.37%, correspondingly but lower amylose (18.29–27.22%) and RS content were obtained by acid hydrolysis starch in contrast to native starch. The modified starch has improved heat stability with smaller breakdown viscosity, and setback viscosity less than native starch, and is easily to gelatinize. ABSTRAKPenelitian ini bertujuan untuk mengkarakteristik pati sagu ihur alami (PSIA) yang dimodifikasi dengan perlakuan hidrolisis asam. Rancangan yang digunakan yaitu rancangan acak lengkap non-faktorial dengan empat taraf perlakuan yaitu PSIA, hidrolisis asam (PSIHA) menggunakan HCl 1,1 N, 2,2 N, atau 3,3 N. Parameter yang diukur meliputi karakteristik fisik antara lain warna, kemampuan menggelembung, daya larut, kejernihan pasta, dan sifat amilografi. Karakteristik kimia meliputi kadar air, kadar abu, dan amilosa sedangkan karakteristik fungsional yaitu kadar pati resistan (RS). Hasil penelitian menunjukan bahwa perlakuan hidrolisis asam menyebabkan perubahan terhadap sifat fisik warna pati dimana nilai kecerahan (L*) pati hidrolisis asam (80,93–81,89) lebih tinggi dibandingkan PSIA (80,29). Sebaliknya nilai kemerahan (a*) dan kekuningan (b*) PSIHA (5,13–6,34 dan 13,21–15,39) lebih rendah dibandingkan PSIA (8,62 dan 18,24). Perlakuan asam juga menyebabkan kemampuan menggelembung PSIHA (43,88–50,65%) mengalami penurunan dibandingkan PSIA, tetapi meningkatkan daya larut (8,92–12,34%) dan kejernihan pasta (74,70–77,73% T). Untuk sifat kimia, kadar air pati sagu hidrolisis asam (8,72–15,01%) dan kadar abu (0,22–0,37%) relatif lebih tinggi dibandingkan pati alaminya, namun perlakuan asam menurunkan kadar amilosa (18,29–27,22%) dan kadar RS (0,06–0,37%). PSIHA memiliki kestabilan yang lebih baik selama pemanasan dengan breakdown viscosity yang lebih kecil dibandingkan dengan PSIA, serta kecenderungan teretrogradasi lebih rendah, yaitu ditunjukkan nilai setback viscosity yang rendah, dan lebih mudah mengalami gelatinisasi.

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