WCO Explanatory Notes reproduced for reference. © World Customs Organization. Verify against official WCO publication.
29.34 - Nucleic acids and their salts, whether or not chemically defmed; other heterocyclic compounds. 2934.10 - Compounds 2934.20 - Compounds containing in the structure a benzothiazole ring-system (whether 2934.30 - Compounds containing in the structure a phenothiazine ring-system (whether containing an unfused thiazole ring (whether or not hydrogenated) in the structure or not hydrogenated), not further fused or not hydrogenated), not further fused - Other : cloxazolam 2934.99 -- Other This heading includes nucleic acids and their salts. These are, complex compounds which, when combrned with proteins, form the nucleo-proteins f o p d in the nucleii of animal yd vegetable cells. The are combinations of phosphoric acids wlth sugar and pyrimidine or purine compounds. Genera ly in the form of white powders, soluble in water. T The acids, or more often their salts (e.g., sodium and cop r nucleates), are used as tonics and stimulants for the nervous system and solvents for uric a c i r The heterocyclic compounds covered by this heading are : (A) Compounds containing an unfused thiazole ring (whether or not hydrogenated) in the structure. . The term "thiazole" includes both 1,3-thiazole and 1,Zthiamle (isothiazole). (B) Compounds containing s benzothiazole ring-system (whether or not hydrogenated), not further fused. The term "benzothiazole" includes both 1,3-benzothiazole and 1,2-benzothiazole (benzisothiazole). This part includes, inter aZia : (1) Mercaptobenzothiazole. White-yellowish fine powder. Used as an accelerator in the rubber mdustry. (2) Dibenzothiazolyl disulphide. Used as an accelerator in the rubber industry. r, (3) Ipsa irone @W)(2-[4-(4-pyrimidin-2-ylpip&none 1dioxide). Used as an anxiolytic. - 1- y1)butylj 1,2-benzothiazol-3(2H)- (C) Compounds containing a phenothiazine ring-system (whether or not hydrogenated), not further fused. This part includes, inter alia : Phenothiazine (thiodiphenylarnine). Sparkling yellowish flakes or grey-green powder; used for the preparation of dyes, etc. @) Other heterocyclic compounds. This part includes, inter alia : (1) Sultones. These may be considered as internal esters of hydroxysuIphonic acids. They include the sulphonephthaleins, for example : (a) Phenol red (phenolsulphonephthalein). Used in medicine and as an indicator in analysis. (b) Thymol blue (thymolsulphonephthalein).Used as a reagent. (c) 1,3-Propanesdtone. (2) Sultams. These may be considered as internal amides of aminosulphonic acids. They include naphthosultam-2,4-disulphonic acid, obtained &om periacid, and which is used for the manufacture of SS acid (8-amino-1-naphthol-5,7-disulphonic acid or 1amino-8-naphthol-2,4-disulphonic acid). (3) Thiophen. Found in coal and lignite tars. Also obtained synthetically. A mobile, colourless liquid with a benzene-like odour. (4) Furazolidone (INN) (3-(5-nitrofurfurylideneamino) oxazolidin-2-one). (6) Adenosine tri- or pyrophosphoric acid. (7) 3-Methyl-6,7-methylenedi0acy-l-(3,4-methylenediobel)isoquinoIine hydrochloride. This heading excludes mercury nucleates answering to a description in heading 28.52, and cyclic polymers of thjoaldehydes (heading 29.30). Certain substances of this heading, which are regarded as narcotic drugs or as psychotropic substances under international instruments, are indicated in the list appearing at the end of Chapter 29.
1.- Except where the context otherwise requires, the headings of this Chapter apply only to : (a) Separate chemically defined organic compounds, whether or not containing impurities; (b) Mixtures of two or more isomers of the same organic compound (whether or not containing impurities), except mixtures of acyclic hydrocarbon isomers (other than stereoisomers), whether or not saturated (Chapter 27); (c) The products of headings 29.36 to 29.39 or the sugar ethers, sugar acetals and sugar esters, and their salts, of heading 29.40, or the products of heading 29.41, whether or not chemically defined; (d) The products mentioned in (a), (b) or (c) above dissolved in water; (e) The products mentioned in (a), (b) or (c) above dissolved in other solvents provided that the solution constitutes a normal and necessary method of putting up these products adopted solely for reasons of safety or for transport and that the solvent does not render the product particularly suitable for specific use rather than for general use; (f) The products mentioned in (a), (b), (c), (d) or (e) above with an added stabiliser (including an anti- caking agent) necessary for their preservation or transport; (g) The products mentioned in (a), (b), (c), (d), (e) or (f) above with an added anti-dusting agent or a colouring or odoriferous substance or an emetic added to facilitate their identification or for safety reasons, provided that the additions do not render the product particularly suitable for specific use rather than for general use; (h) The following products, diluted to standard strengths, for the production of azo dyes : diazonium salts, couplers used for these salts and diazotisable amines and their salts. 2.- This Chapter does not cover : (a) Goods of heading 15.04 or crude glycerol of heading 15.20; (b) Ethyl alcohol (heading 22.07 or 22.08); (c) Methane or propane (heading 27.11); (d) The compounds of carbon mentioned in Note 2 to Chapter 28; (e) Immunological products of heading 30.02; (f) Urea (heading 31.02 or 31.05); (g) Colouring matter of vegetable or animal origin (heading 32.03), synthetic organic colouring matter, synthetic organic products of a kind used as fluorescent brightening agents or as luminophores (heading 32.04) or dyes or other colouring matter put up in forms or packings for retail sale (heading 32.12); (h) Enzymes (heading 35.07); (ij) Metaldehyde, hexamethylenetetramine or similar substances, put up in forms (for example, tablets, sticks or similar forms) for use as fuels, or liquid or liquefied-gas fuels in containers of a kind used for filling or refilling cigarette or similar lighters and of a capacity not exceeding 300 cm3 (heading 36.06); (k) Products put up as charges for fire-extinguishers or put up in fire-extinguishing grenades, of heading 38.13; ink removers put up in packings for retail sale, of heading 38.24; or (l) Optical elements, for example, of ethylenediamine tartrate (heading 90.01). 3.- Goods which could be included in two or more of the headings of this Chapter are to be classified in that one of those headings which occurs last in numerical order. 4.- In headings 29.04 to 29.06, 29.08 to 29.11 and 29.13 to 29.20, any reference to halogenated, sulphonated, nitrated or nitrosated derivatives includes a reference to compound derivatives, such as sulphohalogenated, nitrohalogenated, nitrosulphonated or nitrosulphohalogenated derivatives. Nitro or nitroso groups are not to be taken as “nitrogen-functions” for the purposes of heading 29.29. For the purposes of headings 29.11, 29.12, 29.14, 29.18 and 29.22, “oxygen function”, the characteristic organic oxygen-containing group of those respective headings, is restricted to the oxygen-functions referred to in headings 29.05 to 29.20.