scholarly journals Studies of amino acids for inhibition of aldol condensation and dissolution of polymeric product of aldehyde in alkaline media

2013 ◽  
Vol 3 (1-2) ◽  
pp. 17-23 ◽  
Author(s):  
Hiren M. Bhajiwala ◽  
Harshad R. Patil ◽  
Virendrakumar Gupta
Keyword(s):  
Amino Acids ◽  
Aldol Condensation ◽  
Alkaline Media ◽  
Polymeric Product

scholarly journals Advances in Chemistry of Isothiocyanate-derived Colourants

2009 ◽  
Vol 27 (Special Issue 1) ◽  
pp. S207-S210
Author(s):  
K. Cejpek ◽  
J. Velíšek
Keyword(s):  
Amino Acids ◽  
Essential Oils ◽  
Maillard Reaction ◽  
Heterogeneous Group ◽  
Model Systems ◽  
Alkaline Media ◽  
Reaction Conditions ◽  
Condensation Products ◽  
Amino Compounds ◽  
Methylene Group

This study is focused on the reactions of isothiocyanates (ITCs) in the presence of amino compounds leading to coloured structures <I>via</I> substituted 2-thiohydantoins. A series of complementary experiments has been done and appropriate reaction conditions and structural prerequisites have been defined. Low-molecular colourants isolated and characterised from the model systems can be sorted into three groups. Yellow to red diastereomeric dehydrodimers of 2-thiohydantoin derivatives that contain an acidic methylene group are formed in mixtures consisted of ITCs and amino acids with &alpha;-methylene group in mild acidic to mild alkaline systems. The condensation products of the 2-thiohydantoins with reactive aromatic or heterocyclic carbaldehydes from the Maillard reaction, essential oils etc. comprise a heterogeneous group of mostly yellow colourants. Blue compounds of two types are structurally more complicated structures that arise from <I>N</I>-substituted amino acids and ITCs in alkaline media.

SOME FACTORS AFFECTING THE GERMINATION OF SPORES OF FOMES IGNIARIUS VAR. POPULINUS (NEUMAN) CAMPBELL, AND THE SIGNIFICANCE OF THESE FACTORS IN INFECTION

1958 ◽  
Vol 36 (3) ◽  
pp. 421-437 ◽  
Author(s):  
H. M. Good ◽  
W. Spanis
Keyword(s):  
Amino Acids ◽  
Sugar Content ◽  
Alkaline Media ◽  
Malt Extract ◽  
Factors Affecting ◽  
Extract Medium ◽  
Malt Extract Medium

Spores of F. igniarius collected from different conks at one time, or from one conk at different times of the year, varied significantly in germinability. However, spores collected from one conk within a 3-day period were judged to be sufficiently consistent for use in comparative tests.Spores germinated best on an 8% malt extract medium buffered at pH 4.0. Only a trace of germination occurred on water agar and none occurred on alkaline media. Stimulation by malt extract appeared to be due partly to the sugar content and partly to an unidentified factor.While extracts of the surface wood of aged wounds contained far less of sugars and amino acids than did extracts of fresh sapwood, germination on the former was consistently better. A lower pH appeared to account for most of this advantage but even when the two types of extract were brought to the same pH better germination occurred on the extract of the aged wound.Spores of F. igniarius germinated well at temperatures in the range 20–35 °C. They varied widely in their ability to germinate after storage. Some samples germinated fairly well after 80 days; others failed to germinate after 10 days.These findings are discussed in relation to the problems of infection.

scholarly journals Investigation of the Effect of Nanocrystalline Calcium Carbonate-Substituted Hydroxyapatite and L-Lysine and L-Arginine Surface Interactions on the Molecular Properties of Dental Biomimetic Composites

Biomimetics ◽  
2021 ◽  
Vol 6 (4) ◽  
pp. 70
Author(s):  
Dmitry Goloshchapov ◽  
Vladimir Kashkarov ◽  
Kirill Nikitkov ◽  
Pavel Seredin
Keyword(s):  
Amino Acids ◽  
Fourier Transform ◽  
Infrared Spectroscopy ◽  
Fourier Transform Infrared ◽  
Surface Interactions ◽  
Molecular Composition ◽  
Alkaline Media ◽  
Hydroxyl Groups ◽  
X Ray Diffraction ◽  
X Ray

Differences in the surface interactions of non-stoichiometric nanocrystalline B-type carbonate-substituted hydroxyapatite (n-cHAp) with the amino acids L-Lysine hydrochloride (L-LysHCl) and L-Arginine hydrochloride (L-ArgHCl) in acidic and alkaline media were determined using structural and spectroscopic analysis methods. The obtained data confirm that hydroxyapatite synthesized using our technique, which was used to develop the n-cHAp/L-LysHCl and n-cHAp/L-ArgHCl composites, is nanocrystalline. Studies of molecular composition of the samples by Fourier transform infrared spectroscopy under the change in the charge state of L-Lysine in environments with different alkalinity are consistent with the results of X-ray diffraction analysis, as evidenced by the redistribution of the modes’ intensities in the spectra that is correlated with the side chains, i.e., amide and carboxyl groups, of the amino acid. During the formation of a biomimetic composite containing L-Lysine hydrochloride and n-cHAp, the interaction occurred through bonding of the L-Lysine side chain and the hydroxyl groups of hydroxyapatite, which created an anionic form of L-Lysine at pH ≤ 5. In contrast, in biocomposites based on L-Arginine and n-cHAp, the interaction only slightly depends on pH value, and it proceeds by molecular orientation mechanisms. The X-ray diffraction and infrared spectroscopy results confirm that changes in the molecular composition of n-cHAp/L-ArgHCl biomimetic composites are caused by the electrostatic interaction between the L-ArgHCl molecule and the carbonate-substituted calcium hydroxyapatite. In this case, the bond formation was detected by Fourier transform infrared (FTIR) spectroscopy; the vibrational modes attributed to the main carbon chain and the guanidine group of L-Arginine are shifted during the interaction. The discovered interaction mechanisms between nanocrystalline carbonate-substituted hydroxyapatite that has physicochemical properties characteristic of the apatite in human dental enamel and specific amino acids are important for selecting the formation conditions of biomimetic composites and their integration with the natural dental tissue.

Recent advancement and novel application of organocatalyzed aldol condensation reactions: A comprehensive review

2022 ◽  
Vol 19 ◽  
Author(s):  
Ajay Kumar Verma ◽  
Braj Nandan Kishor ◽  
Om Prakash
Keyword(s):  
Amino Acids ◽  
Aldol Condensation ◽  
Biological Activities ◽  
Condensation Reaction ◽  
Addition Product ◽  
Aldol Reactions ◽  
Hydroxy Ketone ◽  
Unsaturated Ketone ◽  
Condensation Reactions ◽  
Aldol Condensation Reactions

Background: Aldol reactions play an important role in the development of organic synthesis-owing to their critical importance for the forming of carbon-carbon bonds while concurrently one or two chiral centers come into being. In the modern scenario, the Aldol condensation reaction has arisen as perhaps the most significant reaction for the formation of novel medicinal agents exhibits promising pharmacological activities. Objective: The purpose of this study is to present newer synthetic approaches through Aldol condensation reaction for the synthesis of diverse scaffolds to explore the promising various types of biological activities. Methods: Aldol condensation concerns the nucleophilic addition reaction of a ketone enolate to an aldehyde to form aldol or β- hydroxy ketone. Occasionally, the aldol addition product losing water molecule yields an α, β-unsaturated ketone. Results: Results showed that amino acids and all lengths of peptides are utilized as chiral catalysts. As of now, the arrangement of catalysts that have been accounted for is intensely one-sided towards proline. This is to some degree because of its exceptional status among the normally happening amino acids as an auxiliary amine and to its restricted underlying adaptability. Conclusion: The present study thus provides useful insight concerning the promising coherent way for the synthesis of prolinamide analogue of proline, through a direct asymmetric aldol condensation reaction. Thus, the current study summarizes various Aldol condensation reactions for the synthesis of novel agents as well as their promising pharmacological importance.

Phlyctochytrium reinboldtae (Chytridiales): morphology and physiology

1970 ◽  
Vol 48 (3) ◽  
pp. 479-484 ◽  
Author(s):  
D. J. S. Barr
Keyword(s):  
Amino Acids ◽  
Ammonium Nitrate ◽  
Pure Culture ◽  
Carbon Sources ◽  
Alkaline Media ◽  
Nitrite Nitrogen ◽  
Nitrate And Nitrite

A pure culture of Phlyctochytrium reinboldtae Persiel isolated from soil near Ottawa, Canada, grew best at 20 and 25 C, slightly at 10 C, and not at all at 35 C. It grew best in alkaline media and required no exogenous vitamins. It used ammonium, nitrate, and nitrite nitrogen and each of the 7 amino acids tested. Of 18 carbon sources, it used glucose, fructose, trehalose, maltose, mannose, cellobiose, glycerol, and starch. It is similar physiologically to P. punctatum Koch and P. plurigibbosum Barr and morphologically to P. papillatum Sparrow and P. dichotomum Umphlett.

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