INTRODUCTION:

Small bicyclic molecules are frequently found in nature and are attracting increased attention from organic and pharmaceutical chemists. Heterocyclic compounds are acquiring more importance in recent years because of broad pharmacological activities ^[1]. Indanols^[^2] have a particular value due to both their broad spectrum of biological activity and their wide-ranging utility as synthetic tools in the design of various bioactive molecules. Structures of indan-4-ol and indan-1-ol are outlined below.

Figure 1 Structures of indan-4-ol and indan-1-ol

Indanol derivatives show wide range of pharmacological activities. Enantiomerically pure (1S, 2R)-1-amino-2-indanol is an important intermediate of HIV protease inhibitor posses significant Antiviral activity^[^3-4]. Indanols also possess insecticidal ^[5] activity. Benzylated derivatives of the 4-Indanols exhibit Hypotension^[6], Anti-inflammatory ^[6] and CNS depressant activities ^[6].A Propargylamino indan derivative (R enantiomer of N-propargyl-1-aminoindan) is a selective irreversible inhibitor of MAO-B used in the treatment of Parkinson's disease and other neurological conditions. Indanoxy propanolamine derivatives of indanols show significant muscle relaxant property^[7]while Indanoxy acetic acid derivatives of indanols yields compounds with adrenergic blocking and potentiation effect and tranquillizing activity^[8].Given below is a brief account of various biological activities of indanol ring and their derivatives.

PHARMACOLOGICAL ACTIVITIES OF INDANOL AND THEIR DERIVATIVES:

ANTIFUNGAL ACTIVITY:

Strehlke P et al ^[9] synthesized derivatives of 2-imidazolyl-l-indanol as potent Antifungal agents. Vijay K Patel et al ^[10] synthesized a series of indanol acetic acid derivatives as potent antimicrobial and antifungal agents.

ANTIVIRAL ACTIVITY:

Alonso N et al ^[11] synthesized novel 6-substituted purinylcarbanucleoside derivatives of indan from (+-)-trans- and (+-)-cis-3-hydroxymethyl-1-indanol through a key coupling reaction with 6-chloropurine and evaluated for Antiviral activity. The compounds show moderate Antiviral activity.

ANTI-HIV ACTIVITY:

Wang YA et al ^[12] synthesized the (1S,2R)-1-amino-2-indanol, an important component of indinavir, a potent inhibitor of the protease of human immunodeficiency virus (HIV). Formation and enantioselective reduction of oxime ether of 2-hydroxyindanone had afforded (1S, 2R)-1-amino-2-indanol in 97% cis selectivity.

Soo Y. K et al ^[4]synthesized (1S,2R)-cis-1-Amino-2-indanol. It is also a popular structural motif in many chiral auxiliaries and ligands. cis-1-Amino-2- indanol is exemplary. The (1S,2R)-enantiomer is a key component of the HIV-protease inhibitor Indinavir and other related compounds.

ANTITUBERCULAR AGENTS:

Mohammed Ashraf Ali et al ^[13] synthesized large number of indanol derivatives as antitubercular agents.

Figure 2 Structures of pharmacologically active indanol derivatives

HYPOTENSION, GANGLIONIC BLOCK, ANTI-INFLAMMATORY AND CNS DEPRESSION ACTIVITY:

Shapiro S et al ^[8] synthesized large number of Indanoxy acetic acid derivatives of indanols and yielded the compounds with adrenergic blocking and potentiating effects, tranquillizing and anti-inflammatory activities. Of particular interest was hypocholesteremic effect with α-(indan-oxy) butyric acid. Shapiro S et al ^[7] synthesized a series of Indanoxy propanolamines derivatives of 4-indanols and shows significant muscle relaxant property. Some of the related compounds also show CNS depressant, Analgesic, Hypnotics and Antipsychotic activities. Shapiro S et al ^[6] synthesized a series of disubstituted amino alkyl ethers of 4-indanol i.e.7-benzyl-4-indanol and 7-Chlorobenzyl-4-indanol and disubstituted amino alkyl ethers of 5-indanol i.e. 6-benzyl-5-indanol and 6-Chlorobenzyl-5-indanol and evaluated for pharmacological activity. Significant responses such as Hypotension, Ganglionic block, anti-inflammatory and CNS depression were found.

Figure 3 Structures of amino alkyl ethers

CONCLUSION:

Indanol is a unique template that is associated with several biological activities. This article high lightened research work of many researchers reported in literature for different pharmacological activities on different indanol compounds synthesized. This review has presented comprehensive details of indanol analogues, potent compounds reported for particular pharmacological activity. More investigations must be carried out to evaluate more activities of indanol for many diseases whose treatment are difficult in the medical sciences.

REFERENCES:

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2. Rulev AY, Ushakov AI, Nanajdenko VG One-pot synthesis of functionalized indenols from 2- bromoalkenyl trifluoromethyl ketones Tetrahedron 2008; 64:8073-8077.

3. Demir AS, Aksoy-cam H, Camketen N, Hamamci H, Doganel F An Efficient Synthesis of (1 S , 2 R )-1- Amino-2-Indanol, A Key Intermediate of HIV Protease Inhibitor, Indinavir Turk J Chem 2000; 24: 141-146.

4. Soo YK, Kyung MA, Kim AJ Enantioselective Synthesis of Cyclic Amino Alcohols:cis-1-Amino-2-indanol Bull Korean Chem Soc 2006; 27(12): 2019-2022.

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8. Shapiro S, Bazga T, Freedman L, Indanols V. Indanoxyacetic acid derivatives J Pharma Sci 1962; 51(6): 582-587.

9. Strehlke P, Hoyer GA, Schroder E Antifungale Imidazolverbindungen I: Synthese von Derivaten des 2- Imidazolyl-1-indanols und des 2-Imidazolyl-1-tetralols mit antifungaler Wirkung Arch Pharma 1975; 308 (2): 94-109.

10. Patel VK, Sen DJ, Patel CN Antimicrobial and antifungal screening of indanone acetic acid derivatives J Chem Pharm Res 2010; 2(2): 50-56.

11. Alonso N, Caamano O, Fernandez F, García-Mera X, Morales M, Rodriguez-Borgesb JE, Clercq ED ECSOC 2008; 12: 1-30.

12. Wang YA, Wu J, Xia P Synthesis of 1, 1‐Dimethyl‐4‐indanol Derivatives Synthetic Communications 2006; 36: 2685-2691.

13. Ali MA, Samy JG, Manogaran E, Sellappan V, Hasan MZ, Ahsan MJ Synthesis and antimycobacterial evaluation of novel 5,6-dimethoxy-1-oxo-2,5-dihydro-1H-2- indenyl-5,4-substituted phenyl methanone analogues Bioorg Med Chem Letter 2009; 19: 7000–7002.

Received on 16.02.2012 Accepted on 10.03.2012

Asian J. Res. Pharm. Sci. 2(1): Jan.-Mar. 2012; Page 09-11