Hypro

L-proline D-proline DL-proline bydroxyproline [147-85-3] [344-25-2] [609-36-9] (cis) Hypro 4-bydroxy-2-pyrrobdin 131.13... 

Hypro A process for making hydrogen by catalytically decomposing hydrocarbons to carbon and hydrogen. The carbon is burnt to provide the heat for the reaction. Developed by UOP. 

IPS Chimic Chirosolve Ligand exchange Po ly aery lam ide-am ino acids (pro, hypro, val, phe, pip)... 

The Hypro process is a continuous catalytic method (Figure 10-3) for hydrogen manufacture from natural gas or from refinery effluent gases. The process is designed to convert natural gas ... 

Hypro process a continuous catalytic method for hydrogen manufacture from natural gas or from refinery effluent gases. 

The selection of a stationary phase suitable for the GC analysis of all amino acids seemed to be the main problem hindering the wider use of these derivatives, which were always applied to a limited number of amino acids only. For the separation of TFA-amyl esters about 100 stationary phases have been tested, most of which were rejected owing to the decomposition of the acyl derivatives of hydroxyl and thiol groups that proceeds on some stationary phases with Tyr, Ser, Hypro, Thr and CysH. The application of 25% DECS led to the elution of only eight derivatives of amino acids out of thirteen that were analysed [225], The polyester PEGA and the silicones QF-1 and MS-710 [197,227, 228] were reported as the most suitable liquid stationary phases. For the analysis of... 

TMS derivatives of amino acids were also combined with other procedures and some difficulties were thus avoided. N-TMS-methyl and -ethyl esters of most protein amino acids were prepared by the action of TMSDEA on alkyl esters of amino acids and were chromatographed on methylsilicone stationary phases [246], Their retention times were found to be 15—20% lower than those of the corresponding TMS derivatives. Despite having an additional step in comparison with direct silylation, the procedure was applied by Hardy and Kerrin [259] to the GC analysis of twenty protein amino acids, including Hypro and CysH. Amino acids were esterified with a 3 N HC1 solution in n-butanol at 150°C for 15 min with subsequent silylation with BSTFA for 90 min at the same temperature. Acetonitrile and methylene chloride were used as solvents for the silylation. In the former solvent double derivatives of Gly and Lys (bis- and tris-) were produced, whereas in the latter the less silylated form only was produced. As Arg, in contrast to direct silylation, also leads to one peak in this instance, methylene chloride is recommended as the silylation solvent. The separation of all twenty amino acids was achieved on a simple column with 2% of OV-7 on GLC-110 textured glass beads (100—120 mesh). 

Tyr and Hypro, were separated on a capillary column coated with Carbowax 1540 at 102-165°C. On a preparative scale (gram amounts) the yields ranged from 50 to 98%. The application of pivalaldehyde to the preparation of the derivatives is illustrated by Scheme 5.13 (p. 109). Benzaldehyde reputedly reacts with amino acids under moderate conditions [162]. Mere mixing of the methyl esters of amino acids with a pyridine— benzaldehyde—methanol mixture (1 1 10) is reported to be sufficient for the formation of the derivatives. N-Benzylidene methyl esters of amino acids were analysed on SP-400 at 100-280°C. Pro and Hypro did not produce condensation products, however. 

Isopropyl derivatives were introduced by Pettitt and Stouffer [287] and later studied by other workers [288]. They are prepared by reaction with 2-bromopropane in the presence of sodium hydride in dimethyl sulphoxide. The reaction scheme and the preparation procedure were given in Chapter 4 (see p. 64). Except for Arg, all amino acids under study provided the expected derivatives. The hydroxyl group of Hypro was, however, not protected. The derivatives were found to be stable for a reasonable period of time and were analysed on 3% of OV-17. The extension of this promising one-step method to all protein amino acids did not fulfill expectations, however [288]. Some amino acids (Gly, Gin, Asp and Asn) did not provide detectable derivatives and the others led to multiple peaks. Moreover, significant amounts of by-products were produced, which may interfere. Arg provided a single peak, the mass spectrum of which was identical with that of Orn both derivatives resulted from lactam formation. Isoprop derivatives of 23 common amino acids were separated on 5% of-Carbowax 20M on silanized Chromosorb G with temperature programming (50-240°C). 

There are various types of collagen, but they all have similar structures. A crucial component of this structure is repeating sequences of three amino acids, Gly-X-Pro or Gly-X-Hypro, where Gly is glycine and Pro and Hypro are proline and hydroxy-proline. X is any other residue. A -Gly-... 

---