Table 4. — Characteristic infrared absorption frequencies 

 of three toxin samples dissolved in CCl, 



Possible 



Frequency ^ assignment Literature value ^ 



Substance II (bloom sample) 



3,000 (vs) .C-H (paraflinic) 3.000 (s) 



(unsaturated) 



2,400 (s) P-H PH3, 2,327-2,421 



1,422 (br,s) PCaHs 1,450 (s), 1,000 (m) 



-O 

 I 



1,266 (s) +P (0R)2 1,265 (s) 



1,217 (vs) P-OCsHs 1,218 (P-0-aromatic) (s) 



920 (m) P-O-P 970-940 (m) 



867 (vs) P-C (aliphatic) 750-650 (s) 



Substance I (blomn sample) 



2,940 (s), 2,865 (al . -CH3 2,962, 2,872 ± 10 (s) 



2,905 (s) -CH2- 2,926, 2,553 ± 10 (si 



1,730 (m) -CO- 1,700-1,750(8) 



1,460 (m) -C-CHs 1,450 ± 20 (m) 



-O 



1.265 (s), 1,010 (s) .+P (OR)2 1.265 (s). 1.060-1.000 (s) 



1.210 (s) (CH3)3-C-R 1.250-1.200 (s) 



1.080 (3) -CH2-O-CH2 1,150-1.160 (vs) 



1,010 (3) cyclopropyl 1.020-1.000 (m) 



Substance II (culture medium sample) 



2.950 (s) -CH3 2,962, 2.872 ± 10 (s) 



2,900 (s) -CH2- 2.926,2,663 + 10(3) 



-O 



1,263 (s) +P (0R)2 1.265 



1.215 (vs) POCaHs 1.218 (P-O-aromatic) (s) 



667 (vs) P-C (aliphatic) 750-650 (s) 



' Intensity abbreviations: (vs) very strong; (s) strong; (m) 

 medium; (br) broad. 



NUCLEAR MAGNETIC RESONANCE 

 SPECTRA 



The background of nuclear magnetic reso- 

 nance spectroscopy was given by Pople, Schnei- 

 der, and Bernstein (1959). The spectrum was 

 obtained for a 5-percent (w/v) solution of puri- 

 fied substance II (bloom sample) in CDCI3. The 

 spectrum had two signals: one at 6.31t and the 

 other at 9.38r. Tetramethylsilane (TMS) was 

 used as an e.xternal, not an internal, standard 

 to avoid contaminating the sample. 



A spectrum was also obtained of a 1-percent 

 (w/v) carbon tetrachloride solution (2.5 mg. of 

 substance II in 0.3 ml. of solvent). Again, an 

 external standard TMS was used. Signals were 

 obtained at 6.4 (singlet) and 9.45t (singlet, 

 triplet). 



A signal at 6.3t may be ascribed to a methyl- 

 ene group attached to an electronegative atom 

 or moiety, e.g., oxygen. The signal at 9.38t 

 represents an unusually high tau value. One 

 possibility is contamination from silicone 

 grease, though this seems unlikely in view of 

 the precautions taken. The signal intensity sug- 

 gests a second possibility — that the signal can 

 be ascribed to a methylene in a strained ring. 

 For example, cyclopropane (CH2)3 has a signal 



at 9.778t. The presence of a cyclopropyl moiety 

 seems unlikely because of the absence of promi- 

 nent absorption peaks in the 1,000 to 1,200 

 cm.-' region of the infrared region (Yukawa, 

 1965). For comparison, a methylene group in 

 an aliphatic hydrocarbon would produce a 

 signal at 8.75t. 



OPTICAL ACTIVITY 



A Bendix Corporation NFL automatic polar- 

 imeter. Type 143A, fitted with a mercury-green 

 lamp (546.1 m^u,), was used for all optical ac- 

 tivity measurements. The precision of this in- 

 strument is ±0.0002°. 



The instrument was calibrated with sucrose 

 solution (table 5), by the following technique. 

 Exactly 100 divisions (1 complete rotation) on 

 the fine adjustment zero-control knob corre- 

 sponds to 10 m.° ( = 0.01 degree) of rotation of 

 the plane of plane-polarized light. The reading 

 for pure solvent (for a given measurement) 

 was adjusted to zero by using the fine adjust- 

 ment knob, and the reading on the knob was 

 recorded. Next, the test solution was placed in 

 the cell and the galvanometer pointer was re- 

 turned to zero. The reading on the knob was 

 recorded. The difference between the two read- 

 ings (for the solvent and that for the test solu- 

 tion) was converted to millidegrees of observed 

 rotation, a (100 divisions = 10 m.°). 



For all test solutions, the specific rotation 



25° 



[«] was calculated from the usual relation- 



ship (Vogel, 1956) : [a] =100 M/(^pd) , where 

 n is the observed rotation, ^ is the length of 

 the light path, (0.1 dm), p is the concentration 



Table 5. — Specific optical activity of toxin samples at 

 25° C. and 5J,6 mp 



CHEMICAL AND PHYSICAL PROPERTIES OF TWO TOXINS FROM RED-TIDE ORGANISM 



437 



