scholarly journals Tannins and related compounds. VIII. A new type of proanthocyanidin, cinchonains IIa and IIb from Cinchona succirubra. (2).

1982 ◽  
Vol 30 (12) ◽  
pp. 4277-4282 ◽  
Author(s):  
GENICHIRO NONAKA ◽  
OSAMU KAWAHARA ◽  
ITSUO NISHIOKA
Keyword(s):  
New Type ◽  
Related Compounds

Fibrin-stabilizing factor inhibitors. 12. 5-Dibenzylaminopentylamine and related compounds, a new type of FSF [fibrin-stabilizing factor] inhibitors

1975 ◽  
Vol 18 (3) ◽  
pp. 278-284 ◽  
Author(s):  
Kurt Juergen Hoffmann ◽  
Pal Stenberg ◽  
Christine Ljunggren ◽  
Uno Svensson ◽  
J. Lars G. Nilsson ◽  
...  
Keyword(s):  
New Type ◽  
Related Compounds

Synthesis of trans-2,3-dimethoxy-3- (phenylamino)flavanones and related compounds

1998 ◽  
Vol 76 (2) ◽  
pp. 199-204
Author(s):  
Surya K De ◽  
Mrinal G Dhara ◽  
Asok K Mallik
Keyword(s):  
Side Reaction ◽  
Aqueous Methanol ◽  
New Type ◽  
Related Compounds

trans-2,3-Dimethoxy-3-(phenylamino)flavanones (2), a new type of flavanone derivatives, are synthesized from flavanones or 2'-hydroxychalcones in two steps, the first one being a condensation with nitrosobenzenes (Ehrlich-Sachs reaction) and the second an oxidation with (diacetoxyiodo)benzene in methanol. Nitrone formation, an important side reaction of the Ehrlich-Sachs reaction, has also been exploited to synthesize 2 simply by use of an excess of nitrosobenzene in aqueous methanol. Syntheses of several analogues of 2 are also reported.Key words: trans-2,3-dimethoxy-3-(phenylamino)flavanones, 2'-hydroxychalcones, nitrosobenzenes, 3-(phenylamino)flavones, (diacetoxyiodo)benzene.

A NEW TYPE OF CARBOHYDRATE ORTHOESTER: SIDE REACTIONS OF THE KÖNIGS-KNORR SYNTHESIS

1963 ◽  
Vol 41 (12) ◽  
pp. 3074-3080 ◽  
Author(s):  
C. S. Giam ◽  
H. R. Goldschmid ◽  
A. S. Perlin
Keyword(s):  
Silver Oxide ◽  
Side Reactions ◽  
Carboxyl Group ◽  
Acetoacetic Acid ◽  
The Third ◽  
Carbohydrate Derivative ◽  
Ketene Acetal ◽  
New Type ◽  
Related Compounds ◽  
Anomeric Center

A trisaccharide orthoester (IV) is one of the products formed by decomposition of 2,3,4,6-tetra-O-acetyl α-D-mannopyranosyl bromide in the presence of silver oxide. This new type of carbohydrate derivative contains three units of D-mannose linked together through the functional groups of a molecule of acetoacetic acid. The carboxyl group of the latter takes part in the orthoester structure of IV, with one D-mannose unit closing a 1,2-orthoester ring, and another unit comprising the —OR group through its anomeric center; the keto group of the acetoacetate forms a 1,2-ketal structure with the third D-mannose unit. The n.m.r. spectra characteristics of the trisaccharide and some related compounds are described. The following sequence of reactions is consistent with formation of the trisaccharide: 1,2-trans-acetoxyl bromide [Formula: see text] 1,2-cyclic acetoxonium ion (IX)[Formula: see text] 1,2-cyclic ketene-acetal; ion IX and 2,3,4,6-tetra-O-acetyl D-mannose then added to the ketene derivative.Selective degradation of trisaccharide IV yields a novel type of ketal, i.e., 1,2,O-[1-(carbomethoxymethyl)-ethylidene]-β-D-mannose.

scholarly journals Spectroscopic properties of rubber oxygenase RoxA from Xanthomonas sp., a new type of dihaem dioxygenase

Microbiology ◽  
2010 ◽  
Vol 156 (8) ◽  
pp. 2537-2548 ◽  
Author(s):  
Georg Schmitt ◽  
Grazyna Seiffert ◽  
Peter M. H. Kroneck ◽  
Reinhard Braaz ◽  
Dieter Jendrossek
Keyword(s):  
Room Temperature ◽  
Spectroscopic Properties ◽  
Weak Signal ◽  
Model Compounds ◽  
Reversible Inactivation ◽  
Midpoint Potential ◽  
Spectrophotometric Titrations ◽  
New Type ◽  
Related Compounds ◽  
Reduced State

Natural rubber [poly-(cis-1,4-isoprene)] is cleaved to 12-oxo-4,8-dimethyltrideca-4,8-diene-1-al (ODTD) by rubber oxygenase A (RoxA) isolated from Xanthomonas sp. RoxA has two c-type haem centres that show two distinct α-bands at 549 and 553 nm in the dithionite-reduced state. A well-resolved midpoint potential (E 0′) of –65 mV was determined for one haem by spectrophotometric titrations in the absence of dioxygen with dithionite and ferricyanide as reductant and oxidant, respectively. The midpoint potential of the second haem was not resolvable (E 0′ about −130 to –160 mV). One of the two haems was reduced by NADH (549 nm α-band), similar to bacterial dihaem peroxidases. Evidence for an electron transfer between the two haems was provided by slow reduction of the second haem (553 nm α-band) upon incubation of the partially reduced enzyme at room temperature. Addition of imidazole or related compounds to RoxA led to UV/vis spectral features similar to those observed for partially reduced RoxA. Notably, reduction of RoxA with dithionite or NADH, or binding of compounds such as imidazole, resulted in a reversible inactivation of the enzyme, unlike dihaem peroxidases. In line with this result, RoxA did not show any peroxidase activity. EPR spectra of RoxA as isolated showed two low-spin Fe(III) haem centres, with apparent g-values of 3.39, 3.09, 2.23, 1.92 and 1.50. A weak signal in the g=6 region resulting from a high-spin Fe(III) haem was also observed with a preparation-dependent intensity that disappeared in the presence of imidazole. Attempts to provide spectroscopic evidence for binding of the natural substrate (polyisoprene latex) to RoxA failed. However, experimental data are presented that RoxA is able to subtract redox equivalents from its substrate or from model compounds. In conclusion, RoxA is a novel type of dihaem dioxygenase with features clearly different from classical cytochrome c peroxidases.

scholarly journals Role of Spiral Steroids in Pregnancy and Pre-Eclampsia

2021 ◽  
Author(s):  
Fred Chasalow
Keyword(s):  
Small Samples ◽  
Endogenous Hormones ◽  
Synthetic Compounds ◽  
Endogenous Compounds ◽  
New Type ◽  
Related Compounds ◽  
In Pregnancy

My laboratory discovered a new type of steroids. The structure of these steroids is unique in three ways: (i) they have 23, 24 or 25 carbon atoms – no other known vertebrate steroid has more than 21 carbon atoms; (ii) they are phosphodiesters – no other steroid phosphodiesters are known; and (iii) some of them have a spiral steroid at carbon 17 – no other endogenous spiral steroids are known. In total, our laboratory had elucidated the structure and path of biosynthesis for more than 20 related compounds. We have developed an LC–MS method and a MS–MS method to measure the compounds in small samples (< 1 ml). Synthetic compounds with similar spiral steroids (e.g., spironolactone) function as potassium sparing hormones but there were no known endogenous hormones with this function. We propose that the natural spiral steroids have that function. Endogenous compounds with these functions would have important roles in the physiology of pregnancy, pre-eclampsia, and eclampsia. This chapter will review the proposed physiology and pathology of the spiral steroids during pregnancy. There are many details to confirm but this is a useful paradigm.

ChemInform Abstract: FIBRIN-STABILIZING FACTOR INHIBITORS PART 12, 5-DIBENZYLAMINOPENTYLAMINE AND RELATED COMPOUNDS, A NEW TYPE OF FSF INHIBITORS

1975 ◽  
Vol 6 (26) ◽  
pp. no-no
Author(s):  
K. J. HOFFMANN ◽  
P. STENBERG ◽  
C. LJUNGGREN ◽  
U. SVENSSON ◽  
J. L. G. NILSSON ◽  
...  
Keyword(s):  
New Type ◽  
Related Compounds

The hydrazinolysis of heterocyclic compounds. II. 6-Amino-4-hydroxy-1-methylpyrimidine-2(1H)-thione and related compounds

1975 ◽  
Vol 28 (11) ◽  
pp. 2435 ◽  
Author(s):  
RG Dickinson ◽  
NW Jacobsen
Keyword(s):  
Heterocyclic Compounds ◽  
Ring Transformation ◽  
New Type ◽  
Related Compounds

The reaction of 6-amino-4-hydroxy-1-methylpyrimidine-2(1H)-thione (3) with hydrazine is shown to follow at least three pathways to give 4- amino-5-hydrazino-1,2,4-triazole-3-thiol (1), 5-hydrazino-pyrazol-3- ol(5; R = NH2), (4-amino-5-mercapto-1,2,4-triazol-3-yl)acetohydrazide (4) and triamino-guanidine (6). Similarly, 4,6-dihydroxy-1- methylpyrimidine-2(1H)-thione (18) yields (1) and malonyl dihydrazide (19), and (4). By contrast 4,6-diamino-1-methylpyrimidine-2(1H)-thione (21) does not follow any of these pathways. Formation of (4) represents a new type of ring transformation of pyrimidines. Mechanisms of the reactions are discussed.

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