Key words phosphoric acid - deprotection tert-butoxycarbonyl group peptide synthesis

In a previous report (1) the isolation, toxicity and some chemical data concerning the lipopolysaccharide endotoxin of Neisseria gonorrhoeae was described. The present investigation includes the following: (a) an improved modification of lipopolysaccharide phosphoric acid ester preparation; (b) hydrolysis of lipopolysaccharide phosphoric acid ester and removal of fatty acids; (c) separation of ...

The present work deals with enzymatic hydrolysis of sweet sorghum bagasse to fermentable sugars. The bagasse was treated with phosphoric acid and sodium hydroxide prior to enzymatic hydrolysis by commercial cellulase and β-glucosidase. The phosphoric acid pretreatment was performed at 50°C for 30 min, while 12% NaOH was used for the alkali treatment at 0°C for 3 h. The phosphoric acid pretreatm...

introduction in this study, we have investigated the effect of using phosphoric acid on bonding efficacy of an all-in-one adhesive system, after salivary contamination of dentin. methods and materials eighty-four extracted human molars were prepared for their superficial dentins to be exposed. the molars separated into 7 groups. group 1 specimens were not contaminated. in groups 2-4, samples we...

The study evaluated the effect of salivary-contaminant removal methods on the bond strength of resin cement to hydrofluoric acid-etched ceramic. Treatment with a new cleaning paste resulted in bond strengths not significantly different from those obtained in phosphoric acid-treated, hydrofluoric acid-treated, and uncontaminated control groups; thus the paste may be considered an alternative to ...

BACKGROUND Over the years, it has been known that 34% phosphoric acid is the benchmark in etchants with the best shear bond strength shown with composites in primary teeth. However, with latest technological advancements and innovations, in order to reduce the number of steps and less damage to the tooth structure, non-rinse conditioner (NRC) & Single-Etch and various other etchants have been t...

OBJECTIVE The purpose of this study was to evaluate the effect of casein phosphopeptide amorphous calcium phosphate (CPP-ACP) on the shear bond strength (SBS) of brackets bonded to non-demineralized teeth with either phosphoric acid etching or self-etching primer. METHODS Sixty human premolars were randomly assigned to 1 of 4 treatment groups (n = 15 each): phosphoric acid etching (group 1); ...

This study aimed at testing how active and inactive enamel caries lesions differ by their degree of resin infiltration, and whether the choice of acid pretreatment plays a crucial role. Four examiners assessed 104 human molars and premolars with noncavitated enamel lesions and classified them as 'active' or 'inactive' using the Nyvad criteria. Forty-five teeth were included in this study after ...

A highly efficient Pd-catalyzed ortho-alkenylation is reported using a mono-phosphoric acid-directing group for the first time. This phosphoric acid-directing group is successfully utilized for the synthesis of various alkenylated products and offers a new approach to transition-metal-catalyzed C-H activation.