Iodine → L-Glutamic Acid

HRID 1606827Notes

Reaction equation

HRID 1606827 reaction equation
CC(C[C@H](NC([C@H](NC([C@@H](NC([C@@H](NC([C@@H](NC([C@@H](N[C:84]([C@@H:86]([NH2:92])[CH2:87][CH2:88][C:89]([OH:91])=[O:90])=[O:85])CC1NC=NC=1)=O)CC1C2C(=CC=CC=2)NC=1)=O)CO)=O)CC1NC=NC=1)=O)CC1C=CC(O)=CC=1)=O)C(N[C@H](C(N1[C@H](C(NCC(O)=O)=O)CCC1)=O)CCCN=C(N)N)=O)C.C[OH:94].ClCl.CC1C=C(C2C=CC(N)=C(C)C=2)C=CC=1N.II>CC(O)=O>[NH2:92][C@H:86]([C:84]([OH:85])=[O:94])[CH2:87][CH2:88][C:89](=[O:90])[OH:91]

Participants

6

Reactant 4

HCID 807IodineHCID 887MethanolHCID 44406784pGlu--His--Trp--Ser--Tyr--Gly--Leu--Arg--Pro--Gly--NH2HCID 131710166Chlorine tolidine

Product 1

HCID 33032L-Glutamic Acid

Reagents, catalysts & solvents 1

HCID 176Acetic AcidSolvent2×

Procedure

A stirred mixture of pGlu--His--Trp--Ser--Tyr--Gly--OH (XXXVIII) (16.6 gm) and 1-hydroxybenzotriazole (3 gm) in dry DMF (250 ml) was treated with DCI (4.5 gm) at 0°C and after 3 hours, the dihydrofluoride salt of Leu--Arg--Pro--Gly--NH2 (LXVI) (10.5 gm) and Et3N (3.1 ml) in dry DMF were added and stirring was continued at room temperature for a further 36 hous. The reaction mixture was evaporated in vacuo and the residue was treated with H2O (200 ml). The insoluble DCI-urea was removed and the filtrate was evaporated in vacuo to afford 38 g of crude LHRH. A portion of this (6.47 gm) in 1% AcOH (250 ml) was passed over Bio-Rad AG1-8 (OAc) (1×15 cm) and the filtrate was evaporated in vacuo. The residue, in H2O (15 ml), was chromatographed over CMC (4.5 × 27 cm) and eluted in a stepwise manner with NH4OAc buffers of pH 6.9: (0.005, 0.01, 0.025, 0.075 and 0.1 M). The pooled LHRH fractions, located in the 0.075 M eluate by the Pauly reaction, were lyophilized. The LHRH (3 gm) was further purified by gel filtration over Bio-Gel P-2 (400 gm) (110 cm × 2.5 cm) with 1.3% AcOH. Individual fractions (5 ml) were collected at a flow rate of about 5 ml.min and the pure LHRH was located in fractions 21-31 by the Pauly reaction and by tlc. Fractions showing one spot on tlc were pooled and lyophilized to constant weight affording 2.85 gm. (59%) of pure pGlu--His--Trp--Ser--Tyr--Gly--Leu--Arg--Pro--Gly--NH2 (XXII) (LHRH): [α]D22 -33.9 (c, 0.66, MeOH); [α]D22 -46.6 (c, 0.73, 1% AcOH); Rf1 0.64 and Rf3 0.37, single spot with Pauly, chlorine-tolidine and I2 reagents. Amino acid analysis gave Glu 1.08; His 0.99; Trp 0.87; Ser 0.85; Tyr 0.98; Gly 2.07; Leu 1.04; Arg 1.02; Pro 0.97; NH3 1.08.

Workup

  1. custom(OAc) (1×15 cm) and the filtrate was evaporated in vacuo
  2. customThe residue, in H2O (15 ml), was chromatographed over CMC (4.5 × 27 cm)
  3. washeluted in a stepwise manner with NH4OAc buffers of pH 6.9
  4. customThe pooled LHRH fractions, located in the 0.075 M eluate by the Pauly reaction
  5. filtrationThe LHRH (3 gm) was further purified by gel filtration over Bio-Gel P-2 (400 gm) (110 cm × 2.5 cm) with 1.3% AcOH
  6. customIndividual fractions (5 ml) were collected at a flow rate of about 5 ml
  7. custommin and the pure LHRH was located in fractions 21-31 by the Pauly reaction and by tlc
  8. customaffording 2.85 gm

Sources & evidence

ORD record
ord-329fc832e2714ddc8177644dae9605fc
Source dataset
uspto-grants-1976_04
Patent number
US03953416

Reaction notes

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