Table 1, desloratadine sample IH-NMR data of the DMS0_d6
 The desloratadine 1H spectra of the samples were assigned:
 (I) 1H spectra show that there are 10 groups of hydrogen from low field to high field integral hydrogen ratio was 1: 1: 1: 1: 1: 1: 2: 4:
2: 4, and desloratadine structure match.
 (2) δ 8.334 处 hydrogen as a set of double doublet, number of protons is I, attributed to two hydrogen;
 (3) δ 7.560 处 hydrogen as a set of double doublet, number of protons is I, attributed to four hydrogen;
 (4) δ 7.282 处 doublet hydrogen as a group, the number of protons is I, 12 attributed to hydrogen.
 (5) δ 7.198 处 hydrogen as a set of double doublet, number of protons is I, 14 attributed to hydrogen;
 (6) δ 7.174 处 hydrogen as a set of double doublet, number of protons is I, attributed to three hydrogen;
 (7) δ 7.064 处 doublet hydrogen as a group, the number of protons is I, 15 attributed to hydrogen;
 (8) δ 3.314 处 hydrogen as a group multiplet, 2 protons attributable to 10 hydrogen;
 (9) δ 2.831,2.554 hydrogen groups at multiplet, protons of 4, 18, 20, the home position is hydrogen;
 (10) δ 2.819 处 hydrogen as a group multiplet, 2 protons attributable to 11 hydrogen;
 (11) δ 2.108 处 hydrogen as a single peak, the number of protons is I, home to 19 active hydrogen;
 (12) δ 2.205, 2.002 处 two hydrogen multiplet, protons of 4, 17, 21 bits attributed to hydrogen;  From the foregoing, 1H-NMR spectrum data and the resulting product in this embodiment is of he will be loratadine same structure as the target product.
The value of substituted 3-picoline precursors is illustrated in the synthesis of clarinex (1.22, Desloratadine, Scheme 5), a dual antagonist of platelet activating factor (PAF) and of histamine used in the treatment of allergies. This compound consists of a highly functional tricyclic core with an unsaturated linkage to a pendant piperidine ring. The picoline derivative 1.23 is first treated with two equivalents of n-butyllithium (n-BuLi) followed by alkylation with benzyl chloride to give the chain elongated adduct . The tert-butylamide 1.24 is then dehydrated with phosphorous oxychloride at elevated temperatures to yield the nitrile derivative 1.25. Introduction of the piperidine ring is achieved by utilisation of the appropriately substituted Grignard reagent 1.26. A Friedel–Crafts type acylation promoted by either triflic acid or polyphosphoric acid (PPA) furnishes the tricyclic structure 1.28 which upon N-demethylation affords clarinex (1.22).