NOVELTY - Preparing bivalirudin (I) using a novel nitro protected peptide (II) by fmoc solid phase synthesis technique comprises assembling of peptide chain consisting of 20 protected amino acids on a solid support by coupling to one another; cleaving and deprotecting all protecting groups; and reducing the nitro group on arginine residue of novel protected bivalirudin.    USE - The method is used for preparing bivalirudin (I) using a novel nitro protected peptide (II) by fmoc solid phase synthesis technique (claimed). The bivalirudin (I) is used in the treatment of unstable angina for patients undergoing percutaneous coronary intervention/percutaneous transluminal coronary angioplasty (PCI/PTCA).    ADVANTAGE - The preparation method is improved, cost effective, and convenient process for large scale commercial operations. In the method, the building block is substituted by cheap and easily available Fmoc-Arg(NO2)-OH. This replacement has reduced the overall cost of production of bivalirudin. The process also uses environmentally friendly, non-hazardous, industrially convenient nitro cleavage reagent formic acid-Pd/C in place of the normally used hydrogenation at high pressure.    DETAILED DESCRIPTION - Preparing bivalirudin (I) using a novel nitro protected peptide (II) by fmoc solid phase synthesis technique comprises (a) assembling of peptide chain consisting of 20 protected amino acids on a solid support by coupling to one another to obtain a peptide bound resin (III); (b) cleaving and deprotecting all protecting groups to obtain novel nitro protected bivalirudin (II); (c) reducing the nitro group on arginine residue of novel protected bivalirudin to yield crude bivalirudin (I); and (d) purifying the crude bivalirudin by chromatography. The bivalirudin (I) comprises D-Phe-Pro-Arg-Pro-Gly-Gly-Gly-Gly-Asn-Gly-Asp-Phe-Glu-Glu-Ile-Pro-Glu-Glu-Tyr-Leu; the nitro protected peptide(II) comprises D-Phe-Pro-Arg(NO2)-Pro-Gly-Gly-Gly-Gly-Asn-Gly-Asp-Phe-Glu-Glu-Ile-Pro-Glu-Glu-Tyr-Leu; and the peptide bound resin (III) comprises Boc-D-Phe-Pro-Arg(NO2)-Pro-Gly-Gly-Gly-Gly-Asn(Trt)-Gly-Asp(OtBu)-Phe-Glu(OtBu)-Glu(OtBu)-Ile-Pro-Glu(OtBu)-Glu(OtBu)-Tyr(OtBu)-Leu-Resin, where the sequences are given in the specification.